Gross.
Are there games about 9/11?
Yes.
New York Defender, an Internet flash game were players attempt to shoot-down hijacked airliners before they crash into the twin towers, was published on Newgrounds less than 24-hours after the attacks. There's also
8:46, which is a 2015 simulation video game that takes place on the 101st floor of the North Tower. The game has the player listen as co-workers call their loved ones and slowly realize the finality of their situation before choosing to die by smoke inhalation or jumping out the window.