I've got an idea....but since your son sounds an awful lot like my son, and we're looking at almost the exact same scenario for him, I'm going to ask for just a couple more things before I give you my answer....and tell you where we stand based on talking to a couple college coaches and some people with a VERY GOOD track record with helping kids get into a college that fits them.
1) You mentioned undersized/lacks power. Height/Weight? By lacks power you mean what? Any home runs in HS or travel ball?
2) Does he want to pitch or play 2B? 84mph for a RH is D3 at best...unless he's got crazy good stuff. What is his goal? If he's undersized in height/weight, is a 6-8mph improvement in velocity over the next couple years really a possibility?