The Saab accessory drive (serpentine) belt is self-tensioning by means of a tensioning pulley. Excessive play means that the current belt is spent and must be replaced. It is a very good idea to replace the idler pulley above the tensioner pulley at this time as the bearings fail over time. You can get an aftermarket pulley of machined billet aluminum construction with a repalceable bearing race from Wazee Pulleys
. This pulley is superior to the stock one in just about every conceivable way.
To remove the belt you will need a 1/2 inch socket extension bar that will fit exactly in the top of the tensioning pulley housing and a six mm allen key which you will use to lock the tensioner assembly into this position relaxing the belt. This site
shows the proper routing of the stock belt and the routing procedure to bypass the highly failure prone center idler pulley if your car has that (yours should not), as well as the procedure to remove and fit a new belt. Note, the belts shown on this site are for the short-belt modification only. See also, this site
for additional information. Another diagram is here
with part numbers for the pulleys and the belt.
To remove the belt, you will find it best to remove the airbox to allow you more room at the top end to work. Also, jack up the car and remove the passenger wheel to give you access down below.