We closed on Thursday, Oct. 8 and was wondering the same thing. I was told up to 10 days. I think I will call this Wednesday. We want to make reservations for February.
We just closed on Tuesday, October 6th and received an e-mail from DVC with a one-time activation code to get into the member website on Thursday, October 8th. I called on Saturday, October 10th, was provided with my membership number, and was able to make my first reservation.
I would call every day because it's quite likely you're already in the system.
Checking daily is not a bad idea and if you are not in the system by October 19th give your associate call so they can check with Disney and make sure they have everything they need.