NEW YORK—Even before the first note, there were a pair of standing ovations—one when the chorus filed in and another when concertmaster Benjamin Bowman walked on to tune up the orchestra. About 90 minutes later, when conductor Yannick Nézet-Séguin relaxed his arms, the 3,600 people filling the seats of the Metropolitan Opera House responded with 8.5 minutes of thunderous applause, bringing wide smiles and hints of tears to the 200-plus performers on stage. For the first time in 550 days, an audience was inside the auditorium at Lincoln Center for the Performing Arts on Saturday night, attending a poignant performance of the Verdi Requiem. The night was in commemoration of the 20th anniversary of the Sept. 11, 2001, terror attacks but in fact marked much more. The company was performing in its home for the first time since hundreds of thousands of deaths caused by the coronavirus pandemic, including Met …