On 9/11, the attackers were all Sunni Muslims, many of them from Saudi Arabia, all associated with the al-Qaeda organization. The al-Qaeda organization is an enemy of Iran because of the Sunni-Shia split. We saw a lot of this in Iraq in the violence in the post-invasion period when al-Qaeda-related Sunni groups spent as much time killing and slaughtering Shia citizens of Iraq as they did American forces and others. So there is no love lost between al-Qaeda and Iran, and we don't really see a partnership on that element.
As for Saudi Arabia, Saudi Arabia has concerns about Iran, and its relations are difficult, but as neighbours, they need to work it out. They are not in favour of any kind of a military strike against Iran. They see that as causing more problems. There are difficulties back and forth. I wouldn't say they're enemies, but there are difficulties in the relationship.