A lot of posters have commented on this already. Good discussion, I’ll add to it.
I see what you’re saying, but I think you’re hyper focused on one lifetime stat. You’re ignoring the big picture. He was drafted based on raw top end talent and potential over production. Having some ugly stats his first season is completely understandable.
His prospect status is much more nuanced than his lifetime WHIP since HS. His college WHIP is pretty much irrelevant now. All of his stats, including WHIP, were much better his first year in the minors then his two years in college.
His improvement throughout the season was substantial. He had 5-6 starts in A-ball and was very good. When promoted to A+, he struggled. He got better and his last two starts were dominant:
10IP, 4H, 5BB, 17K, 1ER, .9 ERA, .9 WHIP
This is the guy who’s the #9 prospect.