IB Schools in Bangkok

Hi! I'm currently looking for an IB school for my almost 6 year-old for placement on January Protected content . I have tried asking NIST and Bangkok Patana but they both have waiting lists, and I expect ISB will also have one. KIS does have limited slots left and I'm wondering if anyone have any personal experience with this school. It is a little far from Sathon though but we do have the option to move if need be.

My son is currently studying in an International School in Singapore and we're looking for an IB school because we think the Inquiry-based method of learning is working for him. We will be in Bangkok for 18 months to 2 years then we'll be moving back to Singapore, then eventually probably back to the US or UK. He is into swimming, tennis and soccer.

Any information about these schools and other international schools will be great! Thanks in advance!