That is such murky territory that any answer requires some degree of speculation.
What is clear is that the Bush administration ignored direct warnings from the CIA regarding credible threats of attacks from Al Qaeda within the United States, and both the FBI and CIA were aware of the identities of some of the hijackers previous to the attacks.
Additionally, the Bush administration overtly and continuously lied about the presence of WMD’s (Weapons of Mass Destruction) in order to justify their offensive invasion and continued occupation of Iraq.
So, whether they were complicit in allowing 9/11 to occur through malice or incompetence is almost irrelevant because it was still used as a carte blanche excuse to push pre-existing neo-conservative foreign policy objectives.