for the 9 and 11 year old - definitely CSR.
for the younger one - might go with POFQ.
Coronado Springs by a wide margin. It's the 2nd best pool on property, after SAB.
Sab?
How does POR rate with CSR?
I go to WDW several times a year and normally stay at a moderate. I agree with everyone else that CSR definitely has the best pool among the moderates by a landslide. PORS would probably rank second, then POFQ. CBR has a really nice looking main pool, but it's way too small for that size resort. I have never seen it when it wasn't jammed packed.
Off topic, but CSR also has the biggest hot tub on property.