"A measure of abnormal long put volume was also examined and seen to be at abnormally high levels in the days leading up to the attacks. Consequently, the paper concludes that there is evidence of unusual option market activity in the days leading up to September 11 that is consistent with investors trading on advance knowledge of the attacks".[67] —Allen M. Poteshman, The Journal of Business
I definitely think that the outlandish conspiracy theories (jet fuel / steel beams) were pushed to remove credibility and shift focus from the very legit ones with strong supporting evidence