Sorry I mixed up 409a with 83b. I meant 83b.

At one point, anyone on visas other than business/visitor could file for SSN or a Tax ID. That's no longer possible unless: 1) You are in the US on a legitimate Visa that allows you to work & 2) You have an offer letter for paid employment.

Now students on F1 visa (who are allowed to work part time on campus) can't get SSN unless they pick up a job and have a letter to prove it. Earlier they could.