My 13 year old daughter has been in Edge the last two cruises and she is so much happier there. She really didn't like the younger clubs once she got to about 10 years old. She complained about being in with tiny kids and feeling like the activities were really geared so much younger. It's funny because she otherwise will hang out with lots of kids of different ages. She goes to a private school with mixed age groups that play together so I'm not sure why it was such an issue on the cruise. And she's a gymnast on a team with a variety of ages. One of her close friends at gym is 10. I think it was the activities she didn't like. And the mayhem. She doesn't do well with lots of noise and chaos (has some sensory issues - movies are a problem, for example). She finds the tween club to much more chill. She does enjoy the activities there better, but she also was really happy to go and meet some other kids her age she could hang out with at the pool or go get a snack with, etc.
Make sure your kiddo goes on the very first day. They do meet and greet type activities on that day and it really can set the tone for the week. It may have been the cruises we were on, but my daughter said that they were asked about the kinds of activities they wanted in Edge, which she really liked. Sometimes it is just chill out and play games or color or whatever, but my daughter overall just really prefers the lower key vibe there.
In terms of being about the ship on their own, my daughter has had this privilege since she was able to check herself out. She has either a waist pouch or a cross body bag and the rule is that anytime she moves to a different space she has to send us a message through the app and let us know where she's going and with whom. We've not had an issue with this. Early days her only options were kids club or stateroom. If she checked herself out, she had to go straight to the room and let us know. Now we give her a little more freedom, but she still has to tell us where she is and who she's with. Mostly she's either in Edge, the stateroom, or getting a snack, or doing an activity (trivia, crafts, Who Wants to Be a Mouseketeer, etc.) She's also not allowed to go into another person's stateroom. So if she has a new friend on the ship, that person may not be in our room and she is not able to be in their room. This is just for safety reasons. We really don't know these other families and I would hope they have integrity but dang, you just don't know these days.