Per a Chicago publication, Pinson ended as the 9th best player in the area in the 2018 class.
https://www.suntimeshighschoolsports.com/2018/04/27/late-blooming-seniors-highlight-class-2018-prospect-rankings/
The guy who wrote this piece watches a lot of basketball and has had some good scouting takes over the years. He had Robert Covington (now of the Sixers) as an under-the-radar guy way back when.
That said, Pinson wasn't on his board in the spring, and he wasn't the featured player on his HS team, so there was going to be a limit to how much he moved up.