"Son asked paid sports recruiter guy and got a different answer though. He said that based on Son's late blooming , there are always kids who sign in winter-spring and there are more spots than you would think"
If by late bloomer you mean - started throwing 96 last week. Then you need to have him on a flight to meet you in Jupiter and tape a sign to his back that says "Uncommitted 2019 96mph"
Kidding aside this just isn't accurate information. D1 coaches are done going to showcases and games looking for 2019s. Always be wary of the sports recruiters, especially if they've never seen your kid play. If you're being billed monthly or semi annually this sounds like they're trying to squeeze a few more checks out of you. On Nov 15, there will be almost no scholarships remaining. Especially at some of the big local CA schools which are on the national scene every year and account for draft when recruiting.
As for the offer. Your son is going to miss application deadlines if he does not make a decision soon. It is late. Very late. Coaches and ADs are preparing paperwork for their end of the NLI. You're really playing with fire and risk losing the only offer you have for something that will likely never happen