These would be perfect for your 9 year old. That's right around the age my daughter was when she was wearing these and other training bras. Elizabeth :)
I just went and looked at these again. I'm a 32/34 and there is no way these would fit me, so definitely not women size ;) I think the pink belts I have listed would fit and I'm posting some PJ's later that would also possibly fit.? I hope I was able to help :)