It was an evening of epic proportions on Saturday night at the Kennedy Center, as the National Symphony Orchestra sounded the final triumphant bars of Beethoven’s Symphony No. 9 in D minor — to the most roaring reception I’ve ever heard in the doing so, maestro Gianandrea Noseda also closed the final chapter of the NSO’s ambitious 1½-year celebration of “Beethoven & American Masters,” a festival that reimagined what could have been a run-of-the-mill Beethoven cycle with well-selected symphonic works by William Grant Still and a survey of George Walker’s five deceptively titanic unexpected and, I hope, lasting side effect of this combination of composers is the fresh shine this experiment has put on the NSO — an orchestra whose approach to contemporary work feels less and less fraught with the weight of obligation. Especially so with its string of scintillating accounts of Walker, this is an orchestra that has proved itself — to tilt a phrase in another angle — open to interpretation. Much of Saturday night’s excitement was understandably reserved for the grand finale of this grand finale. But the orchestra’s investment in and embrace of the work of Walker and Still deserve their own rounds of applause. This is the kind of programming that’s helping to remake this orchestra before our 1801 overture to “The Creatures of Prometheus” opened the program. A five-minute snack commissioned by the Imperial Theater to introduce Salvatore Viganò’s libretto, it was an overture to overtures for the 30-year-old Ludwig. With sensibilities proximate to Beethoven’s First Symphony of roughly the same time and the same key of C major, it made a light and lively conceptual bookend to the Ninth, which loomed on the evening’s horizon. It also seemed intended to demonstrate that Beethoven’s musical career can be followed like a breadcrumb trail to the wild omnibus of the Ninth. It was a calisthenic take with fiery energy out of the gate, lovely melodic plumes of flute and oboe, and an unexpectedly rocking resolution that had Noseda pulling Townshend-esque windmills to urge dynamic surges from the good portion of my enjoyment in hearing Walker’s five sinfonias over the past year-plus has come from hearing people react to them afterward — commentary usually smuggled from the rows into the lobby out of a sense of politeness and an erroneous presumption of privacy. The general gist of the chatter is the sinfonias are not here to make friends. They lay out no welcome mat. You won’t find yourself humming them while of which is fair enough They aren’t, they don’t, and you won’t. But I suspect the discomfort drawn by so many from their experience of these cataclysmic miniatures is more a factor of their high-def capture of contemporary anxiety. Last year, I white-knuckled through “Strands,” Walker’s Fourth Sinfonia premiered in 2012, a work whose title seems to refer to its own rending of spiritual threads. But it didn’t have me gripping the armrest because it’s ugly, or unpleasant, or — how to put this? — could easily hear Walker’s music as a garish reflection of the world we opt to leave behind when we enter the concert hall, but to my ears, its beauty springs from its in 2004 and arranged in three movements, No. 3 is a model of momentum, a relentless forward fling that crashes through its own obstacle course. On Saturday, the blast of brass and tensile strings that set its universe into motion registered like a sonic boom, and scarcely relented. It’s a work of little respite and few hiding places; breaks in the action are quickly broken open. Even the gentle outcropping of woodwinds that opens the second movement is uprooted in a tsunami of often terrifying sound. What chance does the audience stand?Noseda was especially commanding over the third movement’s mechanistic churn of trombones, hammered bells and rumbling drums. Uncertain strings cut through the din like stark shafts of light as the brass section seemed to bare its teeth. At times, it was tough to discern whether we were building toward a climax or a collapse, the controlled demolition of its finish dropping into unsettling major part of hearing the Ninth is seeing the Ninth, the spectacle it assembles just to exist. On Saturday, the concert hall stage held 65 musicians, 142 members of the Washington Chorus led by artistic director Eugene Rogers, four soloists and an extremely busy Noseda, who helmed its 62-or-so minutes with an affection and affinity he’s been coding into his cells since first performing it in 1995. In his opening remarks, Noseda recalled the Italian conductor Carlo Maria Giulini advising him before that first performance The Ninth “can only be touched with pure and clean hands.”Noseda’s were spotless. One highlight of the maestro’s treatment of Beethoven throughout this festival has been his detailed restoration of the composer’s humanity — a facet of Ludwig often lost in the overstuffed lore of genius. As a composer, as a man, as a body on earth, Beethoven was perhaps never more human than when he composed the Ninth, between 1822 and 1824, and throughout Saturday’s account, Noseda saw to it that the orchestra didn’t play this monument as a monolith — not so much taking orders from the music as drawing the opening shimmer of fifths, the entire string section sounded heightened on Saturday. Sometimes it pays to catch the third go-round of a program. In less sensitive hands, this substantial first movement “Allegro ma non troppo, un poco maestoso” can struggle to cohere, its vast stretch obscuring its peaks and dips. Noseda’s guidance relies on carefully managed dynamics and wayfinding accents, and he masterfully mapped the movement without flattening it. The horns and woodwinds were especially dazzling through the second movement built from its opening fugal snowball to a whirling, properly “Molto vivace” revelry. Only occasionally did the balancing act of this richly textured movement falter The rhythmic pulses of brass that so effectively buoyed passages of the first movement somehow felt too present here. But this is me just hunting for stuff; it was a captivating take invigorated by a Saturday night energy among the players. Principal oboe Nicholas Stovall, principal clarinet Lin Ma and principal bassoon Sue Heineman all made brilliant showings in this not-quite-scherzo’s horns, led by Abel Pereira, were in exquisite form, with fourth horn Scott Fearing offering silken solos through the third movement “Adagio molto e cantabile”, especially beguiling paired with principal flute Aaron Goldman. And its concluding brass fanfares were energizing, beautifully controlled harbingers of the colossus to finales don’t get much grander than this. I’ve been waiting to hear the Washington Chorus tackle the Ninth since word first surfaced of this series, and it did not disappoint. The chorus was wonderfully balanced rich and sturdy lows buttressing the crystalline gleam of the sopranos. No small feat when everything is turned up to the 19th-century equivalent of 11. The four soloists — soprano Camilla Tilling, mezzo Kelley O’Connor, tenor Issachah Savage and bass-baritone Ryan McKinny — all gave fine performances but were helpless against vanishing here and there within the wall of choral sound. Savage had the best night of the four, a magnificent presence with a voice made for joy at a grand before intermission ended, a wise and friendly woman in the row behind me with whom I was chatting remarked that, for every performance of the Ninth, it’s somebody’s first. I offered a little, “Hm,” thinking her thought was done, but it wasn’t. Because every performance of the Ninth, she added, is also somebody’s last. This opened a different door when the symphony started, and when it ended and the hall erupted in applause, I turned to smile and found her in tears. What a gift, either way.