I believe the official story. At most, I think it's possible that the Bush Administration had intel on an incoming attack and turned a blind eye, either out of incompetence or because they knew it would be an excuse to start wars in the Middle East and all the other shit. I believe Israel was happy about it, in the same way Winston Churchill was not so secretly delighted when he heard about Japan attacking Pearl Harbor.

I used to lurk 9/11 Truther circles about 10 years ago. I just never found the arguments convincing. Many were just batshit insane and the product of people who were obviously schizophrenic.