At some of the all star events (pro outdoor) they do fastest shot contests. I think some have shot in the 115 -119 range. Not sure if anyone has ever broken 120. However, to crank that hard in an actual game, you need what is known as a "time and room" shot. I.e. no one is near you, you are roughly 15-18 yards away from the goal and you have 2-3 seconds to wind up and set your feet. In real games against stout defenses, you don't get a ton of those types of oppurtunities save for man up or transition offense.
Even at 100 mph, most goalies can save those shots if they are outside the restraining box (+20 yards). If a defense knows a player has a cannon, the coach will always make sure that the shooter always has someone on their hands so they can't freely wind up.
So while time and room shots are important, how a player, particularly a midfielder, shots on the run is more indicative of their success in college. Stevenson seems like he's got a great shot on the run. His lefty shot even seems strong. Shooting on the run is less about velocity as it is accuracy/placement. The big thing for him will be using his body to get his hands free.
I helped out with a shooting clinic last night for some kids, we had some pro box players helping out. I got out the radar gun to time the kids and the pros. Clocked a few from the pros at over 100. Goalies are insane!