First of all, congratulations! A 900 is a great airplane.
I think you raise a good question, and in return I would ask if the airplane has been flying regularly or has been sitting. On an airplane which has been flying regularly and has good records, I would just keep going and see what happens.
My 980, when I got it, had only flown about 10 hours the previous year, even though it was very well maintained and always in annual. As a result, the sort of issues I had related to valves sticking and that sort of thing. So exercise all of the valves-- fuel shutoff, fuel interconnect, those are the main ones. Avionics can be an issue, but that really depends on what it has in it. If it's been upgraded and has reasonably new Garmin stuff, then it's probably fine. If it's the old original radios, then audio panels can be troublesome.
Also, if it has a Sundstrand, I can't emphasize enough the importance of keeping the oil level up by topping it every 25 hours, and if you don't have good records, I would change the filters. They are ridiculously expensive, so if you have good records and they don't need to be changed then don't, but if you have any doubt, then change them.
Other than that, 900s tend to be solid, reliable airplanes.