Welcome to Saabscene, Tonker.
I wouldn't worry about the timing chain unless it starts to rattle. If it does, though, sort it out straight away. Many 9000s do hundreds of thousands of miles on the original timing chains. There were some problems with the balance shaft chains on early 2.3 engines, which has given rise to rumours that the 9000 timing chain is a weak point. However, this shouldn't affect your 2.0.
Personally, what I would do (what I did do in fact, with a car I bought recently) is go through the service schedule and perform every single item that should ever have been done at any service up to now. You might as well do the fuel filter too, as it will be due to be changed shortly.
The service schedule for '92-on is at
Saab9000.com under "Servicing". If your car is earlier than '92, use that schedule anyway as I think the only real difference was that pre-'92 turbocharged 9000s had a shorter oil change interval. Non-turbo oil changes were always 12,000 miles. There are a few extra items on the later schedule too, which I expect was in light of experience with earlier cars.
One item I would definitely add, though, is to change the rear bushes on the front lower control arms. These wear and cause the steering to feel mushy and unresponsive, as well as making the car feel "floaty" at speed. On the more powerful variants, they contribute to wheelspin and torque steer too. For about £25 in parts and an hour's labour, you can make the steering feel like new.
Check the engine mountings, upper and lower, although I think they are less likely to fail on the non-turbo.
The only other thing I can think of that might catch you out is the gearshift coupler. If you start to find it difficult to get into 1st/2nd/5th/reverse, then this coupler might have started to separate. A new one is cheap and although fiddly to fit, it is not a big job.
I'm sure some other people can point out something glaringly obvious that I've missed.
