They’re kids, & sometimes hanging around is just what kids do, & want to do..
Unless they are actually hurting, damaging, abusing etc,..
Modern teens are under a lot more pressure these days.
Driven by aspirational parents, equally aspirational Schools, the constant fear of ridicule on social media, rampant consumerism driving the need for the latest must-have brands, never ending pressure to fit in etc.
They put up with a lot of crap sometimes.
You’ve no need to feel threatened by them. Why would you ? The vast majority are bored & letting off steam.
The media love you to think that every time a group of teens get together, they are looking to hurt someone.
Sadly, budget cuts have put paid to any local authority provision, & anyone who tries to start any kind of social provision for teens is immediately seen as a pervert.
I have teen age helpers at my Beaver Scout group, & to the younger Beavers they are the epitome of cool; swaggering in with tales of daring do. They are capable of some pretty incredible stuff given the opportunity.