If your grandson performed that way all summer, coaches should be asking him to call...regardless of Sept. 1. Does he play for a travel team that assists with recruiting? Most kids throwing 90 before junior year have offers.
There is definitely more to it than stats. My son hasn’t picked up a bat during summer or showcases since before sophomore year but these were his showcase stats last time he did...he’s now a PO. Can hit for power, when he connects, which isn’t often enough to win the position.