The general rule is don't showcase until you have something to show. Most players wait until Junior year for that reason, unless they're really advanced.
I know a 2025 who just did a PBR showcase this fall. The kid, like your son, is still developing & ended up posting some really poor numbers with a 60 well over 8 seconds. I'm sure he & his dad wish they'd waited. Now he's signed up for more showcases in a mad dash to get his publicized numbers up.
If you want to get him showcase experience & see where he's at without risk, try a smaller showcase (non-PBR/PG) where the numbers aren't posted. My 2024 did a Junior Day Baseball showcase prior to doing a PBR, it was well-run & gave a similar report to the bigger showcases.