I don’t really buy into any of the views that claim 9/11 was an inside job carried out by the Bush administration, or by foreign governments like England, Israel, or Saudi Arabia.
The role of Saudi Arabia in 9/11 is that it is Saudi Arabia that is responsible for fostering and promoting the Wahhabi/Salafist/Qutist ideology that motivated the hijackers. It was the Saudis that created and promoted this stuff and exported it to countries like Afghanistan. https://en.wikipedia.org/wiki/Politics_of_Saudi_Arabia#The_influence_of_the_ulama
The many various renditions of “9/11 Truth” are popular with virtually the entire spectrum of dissenting political opinion.
“The 9/11 conspiracy theories started out mostly in the political left but have broadened into what New York magazine describes as “terra incognita where left and right meet, fusing sixties countercultural distrust with the don’t-tread-on-me variety”
But the various conspiracy narratives are even more bizarre and outrageous than the conventional narrative itself: https://en.wikipedia.org/wiki/9/11_conspiracy_theories
9-11 was what intelligence specialists call “blowback,” i.e the consequences of the US (and Britain’s and Israel’s) backing of Islamist extremism as an alternative to secular Arab national and Marxist movements in the Middle East, and resentment in the Arab world of range of US foreign policy actions. Chalmers Johnson, a former intelligence specialist, described this in detail: https://en.wikipedia.org/wiki/Chalmers_Johnson
Dr. Michael Scheuer, who was the head of the bin Laden tracking unit at the CIA, has explained in detail why Al-Qaeda, who repeatedly claimed credit for 9-11 and blames the 9-11 truth conspiracies on Iran and the Shia, carried out the attacks and has explained in detail exactly what the motives of the terrorists were for carrying out 9/11.https://en.wikipedia.org/wiki/Michael_Scheuer