A real religion of peace would be able to prove they were peaceful with real examples and have no need to pay apologists to pretend.
Terrorism: The use of violence or the threat of violence, especially against civilians, in the pursuit of political goals. Yeppers, 9/11 met that and more.
The smart play would be admitting 9/11 was terrorism, explaining what part of the religion was misunderstood by the perps and how the elite were going to retrain followers, so it never happens again.