There are certainly a plethora of Indoor Child Play Areas throughout Phuket. My daughter insists on having a play - okay the rides are a little old but they please her to no end.
There are also 'soft rooms' throughout Phuket.
Here are some - but not all.
Ocean Department Store - Rides
Tesco / Lotus - Rides and Soft Room
Big C - Rides and big Soft Room
Index - Soft Room