No way to tell how long an engine has been used. Perhaps looking at compression once you get it serviced and installed. With respect to the other parts from the same bike, you might get a feeling from stuff like wear on the shifter rubber or footpegs. Condition of brake pads - should be largely intact after just 9.000 km (I get 75,000+ km out of a set). Same with brake rotors - wear is indicative of number of kilometers and (of course) riding habits. So much depends on how and where the bike was ridden, but you might look at grit-blasting of the triangle behind the front wheel and condition of windscreen.
Unless stuff looks significantly worn, I wouldn't worry about it. Of greater concern is how the engine was stored for the last 20 years. Cylinders oiled? Exposed to the elements? I would pull the plugs and do a visual examination of the cylinders using a borescope before attempting to turn it over.
With respect to mileage, your 93,000 km isn't much to worry about. I sold my '07 with 295,000 km and zero issues. (I have 170,000 km on my 2011)
Welcome from New Brunswick!! (I find myself in Newfoundland every couple of years for riding and camping - was there for 12 days in Jul/Aug this year)
