The invasion of Iraq and the removal of Saddam was in the works well before Sept 11. The attack on the twin towers just provided an opportunity to launch the Iraq War, which is what the Bush White house wanted. Below is a link to a letter from The Project For The New American Century to President Clinton. The 1998 letter urges Clinton to attack Iraq. Several of the letter's signers were key players in the Bush Whitehouse.
There was no legit connection between Saddam and 9/11, but 9/11 did provide cover to launch the ill conceived war.