To be completely fair, I also have "doubts" about 9/11. I'm sure that the people who crashed into the towers WERE islamic terrorists. The issue for me is how much knowledge the security services, or elements within them, had prior to the attacks, and whether they "allowed" the attacks to happen purely due to incompetence, or whether they knew but chose to say nothing for other motives.
How much influence do the Saudi and other relevant governments have high up in the CIA etc and would elements sympathetic to them in the organisation have been capable of suppressing intelligence they had about terrorist attacks. for me there does appear to be a possibility that SOME in the CIA MIGHT have known about it and I suspect that as time goes on we will come some way towards discovering the truth about it.
the racist, paranoid claims of the 9/11 truth movement, which are so often aimed at demonising either Jews or Saudis as a people do not help.
No matter what I think of the US government I don't think even they would have been capable of organising the deaths of three thousand of their own citizens.
However, I do think that there must be an investigation into 9/11 and exactly what happened, however it possibly should wait about ten years or something, becuase right now, so soon after the atrocity, any investigation, by ANY organisation is likely to be highly politicised ...