Kingsman, first, congratulations on a smart and talented grandson.
You seem to be big into deductive reasoning. But, there are serious flaws with some of your number extractions. If your grandson had a 20 or 25 to 1 ratio of hard hit balls in LL, you cannot deduct that he will have nearly half of that at the college level. The funnel from LL to college is far more exponential than that, as is the constant curve of improvement of both pitchers and hitters.
Scholarships - in baseball, it is extremely rare for a player to get a 100% scholarship. In order to do so as a pitcher, you must exhibit top tier measurables and proven in-game consistent success against top-tier college level hitters. You must have already proven you are capable of withstanding the rigors of a lengthy season and many innings on the arm without fatigue. I won't discount the very remote chance that your grandson can somehow come into a college game and, as you describe, get a few guys out if he follows the right type of starting pitcher at the right time with the right arm angle. But that is absolutely 100% not the type of pitcher that they give significant scholarship money to. They only do so for the proven studs who they know they can count on for extended use. The norm for baseball scholarships is much closer to 25% and the type of pitcher you describe, if successful, is much more likely to be a non-scholarship player. Add on top of that the participation in track & field, creating commitment challenges for both coaches as well as scheduling conflicts, and the odds are zero.
You say a pitcher is born, not made. Yes, you have to have a certain level of natural gifts to succeed. But, the days are long gone where a college level pitcher is performing purely with his natural abilities. Every successful college pitcher today has gone through extensive pitcher-specific training to maximize his abilities, usually well before entering his first year of college. Is it possible for your son to make up some ground? Sure but not enough to warrant a full scholarship up front and particularly not if he doesn't come into the equation with a base of high velocity to start with.
You are severely underestimating the talent level and abilities of college hitters. They face plenty of different arm angles and they are generally VERY good at barreling the baseball. Do some arm angles give some players fits still? Sure, but only a few and only when combined with some combination of excellent movement, location and/or velo.
And, with track, how will he address the overlap of seasons, practice and training times, let alone handle both along with a rigorous academic schedule? BTW, although he excelled in HS as a pole vaulter, his current vaulting height will not even come close to putting him at the competitive level at the higher college ranks. So, he will need to fully commit to continued improvement on that front in order to maintain the scholarship he was offered for that focus. He is far better off looking to supplement the payment of tuition through other means. I'm sure this "specialty pitcher" thing is fun to talk about with him, but if you want reality, it's just not.
Please do keep us informed... this is possibly the king of stories when it comes to something we would LOVE to be proven wrong with.
PS - sorry, I was putting this together while the few recent posts were made... some repeat of same message.