It is a difficult one to be absolutely sure. Your readings don't seem vastly different to those other posters report. But, they do seem a bit high compared to most cars running a proper Saab spec 82C stat. There is no obvious reason why the readings changed after you replaced the water pump, unless some scale or sludge was dislodged from the sensor.
Having only owned one Saab, I don't know how much the accuracy and linearity of the gauges and sensors varies between cars. When my car had overheated, the gauge got close to, but not into, the red zone. The only other evidence was that the coolant level had dropped below minimum. I assume it had escaped through the relief valve in the expansion tank cap. The heater core (since replaced) did have a minor leak, but there was no bad coolant smell or fog in the cabin. I now know that the thermo switch and connector had failed. I assumed, but never confirmed, this affected both low and high speeds.
With the fan not working the car would get too hot after being left to idle for 20-25 minutes. This was on a still day (no wind to simulate a fan) with the ambient temp around 4-5C. I switched off when bubbles started to appear in the expansion tank, and I could see coolant flowing through the overflow pipe (boiling point could be around 120-130C with an antifreeze mix in a pressurized system). The fan had not switched on.
Some other things to try:-
Confirm low speed wiring/relay by shorting the blue and black wires from the thermo switch (annoying if you just hard wired the thing!). Short the blue&white and black wires for high speed, you should hear the difference.
A new thermo switch (not from Saab) only cost me about 12 Uk pounds, not that expensive. You could do a boiling water test on the old one. Need to drain some coolant if removing. I managed to swap mine over quickly by just holding a thick cloth over the hole, and didn't spill too much. The part it screws into seems to be plastic on most 9000 radiators, so don't overtighten or cross-thread it.
Ensure the radiator fins, or the A/C condensor in front of it, is not clogged with dirt.
Partial radiator blockage - check for cool spots just after thermostat has opened, at least the parts you can reach safely. I did a 2 part chemical flush on mine, with the thermostat removed. Like with yours, what came out seemed relatively clean. I think it would take very poor maintenance or a serious failure to cause a blockage.
Temperature gauge sender (cylinder head, near thermostat). Haynes manual says resistance drops with temperature. It suggests disconnecting the wire and then grounding it to check the gauge moves correctly from min to max.
It also suggests that if other gauges show erratic readings, the problem may be a voltage regulator on the instrument panel circuit board.
Things like dirty or loose ground wires/straps could potentially cause strange readings. Engine management faults (fuel mixture etc.) can cause higher temps. If it were something like a head gasket I suspect you would have noticed other symptoms.
The car's ECU also reads the coolant temperature, via yet another sensor in the block. To access this though you need a very expensive TECH 2 diagnostic box, with Saab software. See the following for example use with a later Saab V6:-
http://www.trollhattansaab.net/archives/2008/01/tech-2-how-your-saab-talks-to-your-mechanic.html
Worth a try if you know a nearby friendly dealer or mechanic with one of these.
Personally, I would do the cheap and easy checks first. Like you, I would prefer not to wait until the next hot day to discover there really was a problem after all.
Good luck, and let us know how it goes.