Saudis? Yep. Iran? Maybe. But we can be sure of who did NOT help carry out 9/11...the one Chimp Bush invaded and wasted thousands of lives and trillions of dollars...Iraq.
No, you are not certain of that either, because Iraqis were certainly involved, because without Saddam Hussein there would be no ISIS, after all, Saddam harbored the founder of ISIS, the Jordanian Zarqawi, and two or three of his terrorist cells, one of which, in Baghdad, was composed of Egyptians since at least 2002 and was dealing with the Egyptian Zawahiri since 1999. Just as Saddam Hussein’s red-headed General al Dhouri , the same guy who advised Saddam to court the islamists rather than fight them, to build the great mosque, same guy who advised Saddam to impose shariah law on his people before the US invasion and to open his jails to let just the islamists out and not other political prisoners, was the cofounder of ISIS and the guy whose followers led ISIS back into Mosul from Syria.
Bin Laden’s right hand man as early as the Russo-Afghan war and later in his exile in Sudan was an Iraqi engineer/ former soldier named Sa’ad.
Then there’s al Ani, the Iraqi facilitator and former soldier who met with two if the 9/11 hijackers in Malaysia when the USS Cole plot was formulated. al Ani was caught in a Gulf country and later imprisoned in Jordan before being released under the pressure of leftist human rights groups, after which he fled to Saddam’s Baghdad. When searched he was found to have contact information for the 1993 plotters, the NJ cell in the US and a number of other people of interest including people involved in the 1998 US Embassy bombings.
This is one reason the USS Cole trials are so slow. The bombing is intertwined with too many things still going on.