I bought used direct through Tesla for the additional warranty, among other things. That included the ability to Supercharge as soon as I drove off the lot in Ft. Worth.
It's my understanding, when buying direct from a previous owner, they can transfer to the car to you using the app, at the time of sale and you will be able to Supercharge almost immediately.
When I bought mine last March I was convinced I couldn't live without the USS. For what its worth its has been nice having summon and autopark all along. I knew the Intel CPU would become antiquated I just didn't think it would be this soon.