First of all, the temp should not go over 90 and it should not be just under 90. It should be a bit above the last line before 90, somewhere in the region of 82-85. I would guess that your thermostat is not working properly. The temp gauge should be as it is shown in picture 1 and nothing else. The GTV thermostat is known to fail, so don't worry about it, but change it as soon as possible...With an original, 'couse the aftermarket ones are just not good enough and they are even more prone to failure.
The fan kicks in at just over 90
That's too late. It should start when the temp reaches 90 exactly.
Question is - should it get this hot ever?
No. You can even damage your engine...But it could be as well, that the temp gauge isn't showing the correct temp ----- bad temp senzor.
Anyone got any other suggestions I could look into??
I'm 99% sure it's the thermostat, which is only partially open and therefore your engine isn't cooling itself enough. That would explain the high temp and the functioning fan after just a couple of miles. The flow of the coolant from the engine isn't sufficient and it is heating itself very fast.
the fan has two possible speeds
Yes, there are two "speeds" or rather two fans. But you should hear the fan turning on and off as a click in your dash as soon as the temp reaches 90.