I don't know about Booking.com, but last May we booked through Vacation Strategy and was told we'd be in the system about a week to ten days out. Vacation Strategy does not send you anything after you book with them (not even confirmation numbers), so I was a little nervous. I called Bonnet Creek at nine days out and we were not in their system. I waited a couple of days and called back at seven days out. The CM at Bonnet Creek found a reservation in our name for seven nights (we were staying for nine nights

). That's when I got really nervous.

I called Vacation Strategy thinking they had booked it wrong, but was told that most reservations are for seven nights and if over seven nights, it would be booked with two reservation numbers and the second reservation might not show up for a few days. I called Bonnet Creek back a few days later and sure enough both reservations showed up. The CM assured me we would not have to change rooms. Sure enough everything was fine when we arrived.
I booked eight nights through Shelby Resorts this past Sept. He sent me two confirmation numbers (one for seven nights and one for one night). I waited until about five days out to call that trip and sure enough both confirmations were in their system. The CM I talked to that time said that they are not getting the reservations in their system until about a week out.
We currently have ten nights booked for Dec 6th-16th through Aaron Washburn. Several weeks ago he sent me an email listing three confirmation numbers. I won't be calling to confirm those ten nights until about five days before we arrive. I'm afraid there is no use calling any earlier than that.