We love Pop, we have stayed there several times. Its a great value resort and pretty centrally located. Did you book with one of the specialist out there now (free dining, room discount, etc)? Great decor for kids, but rooms are a bit small, I am guessing you went with 2 rooms, may want to make sure they have request for connecting, that will give you a little more space to spread out and relax while little one is resting.
September is a great time to visit, one of the slowest months of the year. It still can be very very hot so stay hydrated and try to plan most activities for mornigns or evenings to avoid the mid day heat. With a 2 yr old a nap will be a must so I would plan to head back to the resort and relax during that time. Maybe parents (or grands) can switch off and some days take the 8 yr old to the pool while little one naps, but we have had our 8 yr old nap often too during our breaks.
Also September is 'free dining' time and if you plan on eating at any of the Table Service restraunst you need to make ADR (advance dinner reservations) now! They fill up fast and it can be next to impossible to find a place with availability same day.
