You might have missed that part where op already said, that using 911 for marketing the game would not be done.
But by the logic of tragic events, there would be a lot of things that could have no media being associated with them. No movies, no games, no books. And what is the reality? There will be a movie being made shortly after any catastrophe about the exact catastrophe - in addition to the regular desaster movies. Real and fictional tragedies are a way to tell drama. And many books are written by survivors of tragedies. It is popular media.
For 9/11 there are so many movies made, that there are click bait list articles about them. The x movies about 9/11 that have attribute y.
https://duckduckgo.com/?q=movies+about+911&ia=web
A game where you can shoot down planes before they crash into buildings is by far the most harmless thing that you will see done in games about the topic. But we all here agree that using 911 as a marketing ploy is not a good thing.