Inappropriate ads. Game rating is 9 years and up. What gives?

First of all, I can’t see where to buy the ad-free version, but the ads are about gambling and today was an ad that appears to be an explicit adult chatting app!! Completely inappropriate for my 9-year old, who just so happens to be the same age as the app’s game rating. How is this acceptable?? Why can’t we have an ad-free version??