None of them have a zero entry pool - you can pool hop to resorts that do have zero entry such as the GF
They all have kids pools and or play areas - OKW pool is great with the kids small pool and the sandcastle area, VWL has a small kids pool in the main WL pool area and BWV has a small kids pool as well along with some Elephant sprayers
With ages 6&9 though and possibly a life jacket for the 6 yr old (not sure how good they are at swimming), the main pools should be ok for them and your nerves as well
Going to the MK on the boat from WL is pretty cool for kids - the WL boat launch is a bit of a hike from the villas
Do you have a car or are you using Disney Transport?
OKW is very relaxed and laid back and actually seems to have the most reliable transport from a bus perspective of all the
DVC resorts
BWV is centrally located - the boardwalk, access to Epcot and MGM, a great pool slide etc.
Have you considered BCV - has the best pool and a zero entry area as well...?
thanks
jaysue