Could Marvel do a comic about Spider-Man stopping 9/11?

DC, Marvel, and other publishers did comics about 9/11:

https://en.wikipedia.org/wiki/List_of_comics_about...

If Marvel, DC or any other publisher did stories about any superheroes or other kinds of heroes preventing 9/11 from happening then the events of those stories would change the whole dynamic of their respective comic book universes. Preventing 9/11 from happening and succeeding would probably drastically alter the realities of those universes, and things would probably have to be rewritten and reestablished. Publishers like to reflect what's going on in the real world, and be up-to-date on what's going on in the real world, to an extent, through their comics. Having a mainstream comic book continuity in which 9/11 DIDN'T happen would not be very realistic.

They could have done this in their alternate universe stories. Stories like these usually take place on other Earths like in DC's and Marvel's multiverses. I don't know about other comic book publishers' multiverses.

They could have had regular stories done in heroes go back in time to stop 9/11 from happening. They could have succeeded but it probably would not have lasted long.

I'd like to think Marvel would do a story that was done in the same vein as that one Booster Gold story DC did, in which Booster Gold kept going back in time to try to stop the Joker from shooting Barbara Gordon and failing each time.

There probably would be backlash from comic book fans if Marvel, DC or other publishers did any stories in which 9/11 was prevented from happening permanently in any mainstream continuity as Rebel pointed out.

I hope this helps and makes sense.

It would be disrespectful towards the survivors of the real-life 9/11.

Unlikely, as there may be backlash to the idea.

There is a comic called Ex Machina where a superhero is elected as mayor of New York City after he stopped one of the planes from crashing into the Twin Towers

Sure. They could put it in their What-If universe.