Average exit velo on statcast for an MLB player has a much wider range because it's being taken in game against elite pitching. In my experience recording exit velos off a tee, the range is usually 3-5 mph from their max out. Someone who tops at 95 off the tee is sitting in the 89-93 range, 75 mph would be a pop up to the pitcher. The OP asks about bp. It's been studied that 1 mph of pitch velocity equates to .20 added exit velo. So bp exit velos should be about 6 mph harder. From evaluating statcast numbers, the above chart is fairly accurate. Stanton, representing likely the most power in the world, would be about 110 off the tee, while a slap hitter like Billy Hamilton would be around 89. The mean max exit velo is 110, so about 97 off the tee with wood. If you do the math yourself and wonder where I'm getting the numbers from my logic is this; the ball reaches home plate 10mph slower than it leaves the hand, so I subtract that from the pitch velo, then do the .20 method, and finally add 2 mph assuming they change mechanics specifically for the tee readings. This comes out to about 13 mph under the statcast max reading.
To be more specific, I would chart it like this: (I've never seen players more than 2 mph diff with bbcor vs wood)
Average JV 75 Good JV 78 Strong JV 80+
Average V 82 Good V 85 Strong V 87+
Average D1 90 Good 93 Strong 95+
Average MLB 97 Good 100 Strong 102+
I'll just say it to save someone the time from typing it; baseball is not the Olympics, measurables are not the be all end all. Also, a 95ev is great, but if you can't run, you're a permanent 1B, and if you have a noodle arm, it also narrows your positions. Be well rounded. All that being said, Peach, that's exciting for your grandson, I'm sure you're very proud and I wish him all the best in his hopefully long career!
So, instead of using the available data from statcast, which is pretty much the gold standard, we should speculate? My point is this: sure, all of these players are capable of generating exit velos off a tee in an artificial setting with no real variables. But a pitched baseball is the biggest variable of them all, and the average exit velo for these players tells me that it really doesn’t matter what is measured off the tee, because on average you aren’t going to produce that during a game.