I'm not at the phone yet, so not a huge help.
My 7 year old has his own Kindle Fire though. We went with Kindle over an Android tablet because we like the parental control options, we like that it's connected to our Amazon account so we can see it all. Also, he's had a Fire since he was 2 (only child, or he would have had to share it). Originally, he had Free Time on it, and that completely limited what he was able to do. Only parental approved apps, and no way to purchase anything. When it was just too old to work anymore (literally, I now use it for my church app, and that's it.), we bought him a new Fire. For the same reasons above, plus the option of Amazon Underground apps - free full app, no in app purchases.
That being sad, we used to let him use YouTube. He liked to watch Lego builds, and a few other channels (Slow Mo Guys, physics videos, the ball of steel channel). But the parental controls on Youtube are crappy. Even with it set up for no objectionable content, a lot of stuff got through. And, he started getting up early to watch it before we were up. So, we just deleted it. And because his Kindle is locked down, he can't download any apps without the parents password.
The delete option is how we regulate most apps. Over use? We delete it, and he has to earn it back. He's working on earning Netflix back right now.