For my first trip at age 10, my parents and I stayed at the Polynesian and its a fond memory for me. Of the three monorail resorts, I think its the most uniquely themed and the most fun for kids. For us living in upstate NY, it was also the most different from anything we're used to at home. From Poly, you can also walk to the TTC for easy access to the Epcot monorail.
As far as TPV rooms at CR, I would not be surprised if the rooms just aren't available yet. I don't recall when availability opens for room only, but I'd find it hard to believe they are completely sold out over a year away. TPV rooms are pricey besides.
As far as renting points, I would have a backup plan booked and in place in case you can't secure points. Its always a gamble unless you are very flexible in dates, views, and resorts. You should also be aware that point rentals are typically non-refundable and can't be changed, usually require payment up front, and you do not receive daily housekeeping. There are point brokers you can engage starting at 11 months out from your date, but they may or may not have owners at your preferred resorts with enough points to cover your reservation. At the 7 month mark, they can use any DVC owners' points so the point availability is not an issue at that time, but availability at the resort may be. Closer to the 11 month mark, I would reach out to David's or any of the other brokers to get on the list and get a sense of what is available, but I would still have a cash reservation booked just in case.