"Had Saddam remained in power, Iran would NOT have taken advantage of the situation as it does now and Al Qaeda would not have spread in Iraq, enforcing its troops with more and more volunteers."

I don't think we could maintained sanctions for another 5-10 years on Iraq, not to mention a longer timeframe. And I think that even continuing sanctions for 2 more years would have been difficult to do diplomatically.
So the question any President would have faced after 911 was to either try to continue sanctions, but with little chance of achieving the result wanted [Saddam complying with the cease fire treaty]. Or simply stop sanctions- and send the message that one doesn't really have to follow treaty agreement in general, and specifically treaties regarding prohibtions against having WMD [chemical/nuclear].
The continuing of sanctions could include variations, such as stricter sanction, looser sanctions, "targeted" sanctions, all of the above or perhaps other ideas along this line.

The route taken was to continued sanctions, but deploy US troops to Kuwait, so as to have the ability to use force as an option and thereby re-establish the military threat that originally made Saddam sign the cease fire agreement in the first place. And with this threat of using force, require Saddam allow the inspector back in to the country.
[Recall that Saddam kicked the UN inspectors out during the Clinton term, and Clinton response was to bomb areas in Iraq because Saddam chose to do this. And this bombing did not cause Saddam to invite the inspectors back in- which was sort of predictable.]

So the question is assuming Raoul or some else was the president of the US in the period after 911?

Continue sanctions and hope Saddam first agrees to let back the UN inspectors, and then after inspectors are back, continue the cat and mouse until such time as UN inspector can verify the Saddam's regime has complied with the cease fire agreement? [Btw, how would you envision this taking?]

Lift sanctions and declare that Saddam has met condition and move to end the No fly Zones, so that one can get US troops out of Saudi Arabia [the continued presence of US troops in Saudi Arabia is ever becoming a political problem and if containing Saddam has ended, then there is even less reason to have US military presence in the Holy Land].

Or what other choice would you make. Do everything Bush did but keep US forces in the middle east in the sand as as target, indefinitely [and adding further disquiet by having sizable US military in the region which is a much bigger footprints than small amount US forces at the Saudi airbase ].