Well, I think KT should be at the very least 10+ due to mentions of topics like s*icide, depression, mental illnesses, and mentions of homophobia/racism/transphobia/sexism, etc.
While both sites are obviously geared towards children and are family-friendly, some posts on KT can be a bit dark and young kids, in my opinion, shouldn't be exposed to that.
KN I think should be 8-9+ because its a lot more young-kid friendly. As long as the child is up for a lot of reading, its perfectly fine.
- Dino/Wilbur/Toby (he/they/xe)