Unaccompanied roaming is, by it's nature, offline-centric.
The primary, actual risks to children who are roaming are those that involve law enforcement and intolerant adults.
What does not present a meaningful risk to unaccompanied children is strangers.
> For my son, Scouts have been wonderful for his independence. Can’t recommend it highly enough.
I was in scouting leadership for 15 years. Units that function in a way that remove adults from the picture are as good as you say. It doesn't come close to replacing what we've taken from kids but it's better than the nothing they have now.