I think that the pool is closing in September? Not sure exactly when. Sorry!
Re staying CSR or not: We never book anywhere under construction, just to be safe. We have had a couple of bad experiences with construction in WDW in the past, so we always book elsewhere until it is completed.
AFAIK, the construction hasn't been a problem for most people staying at CSR as it is fairly localized. However, it is a personal thing how much it bothers anyone. For me, aside from potential noise issues, I pay to stay in WDW partly for the ambiance and that is just not the same when there is construction going on.
Normally, we just LOVE CSR! Hope that you have a great trip wherever you choose to stay!