Everyone will need to be listed on the reservation.
Personally, I wouldn't put ten in a two bedroom even if the 10th person was under the age of three. These bedrooms that sleep 9 are not any bigger than the ones that sleep 8 (except for OKW) and they get very crowded when they get filled with bodies. OKW is the only one I'd consider for a full crowd of 8 (plus one under the age of three) persons.