I don't see the issue, unless I'm missing something. We had 9 together on our last trip.
We stayed in a timeshare in Feb. Three bedrooms, three bathrooms, 2 kitchens.
It was a 2-bedroom unit, that could be connected to a one-bedroom unit. Our daughter, her husband and their 2 babies in the one-bedroom unit. They had portable cribs, a living area, small kitchen and a full bath. They opened a door and walked into our area, the 2-bedroom unit. It had, of course, 2 bedrooms, a HUGE living area with plenty of seating and a full kitchen.
One bedroom was for me and my husband. Our older daughter and her partner had the other. Our teen daughter slept on the couch a few nights, and also slept on the double bed that was in our room-it had 2 double beds.
We had 3 rental cars between us. We all left each day for the same park, and toured semi-together. We kept splitting up and joining up again in the parks. At night, we all drove back to the condo when we were ready to go, and spent evenings discussing our days.
We ate breakfast in the condo, and had plenty of snacks and drinks there. The babies could sleep peacefully in their unit, and the rest of us could still talk in the other half.
We had problems with water leaking in our unit, but nothing that had to do with us having 9 people. The unit actually could technically sleep more.