To make it even worse,that happened

Call a different Avenger?

That or watch in absolute horror as he is unable to help almost 3,000 of his fellow New Yorkers die in a terrorist attack that will change the world going forward. He'll almost assuredly be forced to settle for helping in the aftermath instead of stopping it in it's entirety. I can only imagine how much more awful 9/11 would feel for someone who's not only a New Yorker, but one who's dedicated their life to helping people in danger, stopping tragedies and making the world a better, happier place, just for it to crumble apart into a plume of smoke and rubble before your very eyes as you're helpless to intervene.