I'm going to move this over to toddler sleep Hun since her LO is nearly 1. In the meantime I'm thinking you may need to make the push to 1 nap after you pick up your other LO from preschool. If his normal WU time is 8:30am and he's going down for a nap at 11:30 that is a pretty low A time for his age, so I'm thinking he should be able to handle a longer A until you return from preschool pick up.