The Senate Committee report, IIRC, supported, via the statements of KSM, that Moussaoui was not part of the 9/11 crew, but was maybe for a "second wave" attack.
A curiosity (maybe not so curious) of the report was selection of statements by KSM that he was too bush with 9/11 plans to deal with later actions - then the Afghan invasion messed up things for AQ...which led me to ask the question "So what?" What was the idea of the second wave plan of attack? Cropdusters perhaps?
What was on Moussaoui's computer when it was seized? That might answer, or partially answer, the question of what the second wave was to consist of, if Moussaoui was part of those second wave plans.