The kids were described as “playing” in the neighborhood before they broke into the house. I don’t think teens would be described that way. I think they’re probably under 12. 9-yr-olds can do some rotten stuff, and are capable of more than they are usually given credit for.
Don’t think of 9-yr-olds in today’s terms, when children are infantilized-- think of when you were 9, if you are now older than 40. Especially if you are older than 50. Did you do things like mow the lawn by yourself, or stay alone in the evening with a younger sibling? Ride your bike out to run errands? or to and from school?
When I was 10, I walked three blocks from my school to the city bus stop, got on the correct bus, got off about five blocks from our apartment, walked to a row of shops and bought something for a snack, then walked home, asked the front desk for the key, and stayed in the apartment by myself for about 90 minutes. In Moscow. Sometimes I went to the cafe on the floor above ours for a cup of tea.
Fairly young kids are pretty capable, whether we admit it or not.