Your best bet is to get the Haynes manual for the 9000. It explains how to remove the interior panels in an easy to understand format. I am able to do it now without even using the manual.
The fan is not directly linked to the ACC system as it just draws in air from knee level & expels it across the window.
The only problem you have is whether the fan is at fault or if the switch needs changing. You can get used fans from Saab dismantlers such as 'www.neobrothers.co.uk'. I've found them to be ok.