Hi Op
I had a feeling you could be a high achieving and have ADHD,
And I was busy checking on Google that was the case but ah I see a couple of Posters have Comfirmed that which is good..
(I really think that encouraging to have a go, take up interests he is curious about or look fun an interesting, be open minded about him exploring new interests,
For e.g team sports or/ndividual sports activities.
Athletics, basket ball team sports, etc
Gymnastics, football,
I think Martial Arts displines he would I think find, fun,good way of exercising,and help to build up his cofindence if its low self cofindence he is desperate to fit it, the gang,for e.g "such taking one for the team,you didn't grass us up"
Its normal for teenagers to rebel part of growing up/independence,
I do get why you are really concerned as he looks like he is starting to go rails.
I would really look at all different kinds of spectrums of behaviours such ADHD, Austim,Asperguers syndrome etc,(as its more common for boys to be diagnosed with these kinds of difference's obvious girls can too.
As it would explain the impulses ness tendancy, your son has got, its one of classic signs, amongst others.
I agree with the Poster,
Who said your son trying "safe risk outdoor activities" such as rock climbing BMX bike rally's, skaterboading etc.
Also think water sports such as swimming /water team sports.
being getting involved in voluntary charity activities for.e.g st John Ambulance /Boy scouts,etc
Does he like Nature/animals?(i wonder if there is charities like that who would be quite happy to have a young, volunteer help out for an hour or so.
Also interests like photograpy would he be into this idea?
Skills like doing Cookery,
Has for a artistic side to himself, creative arts..
There's lots of possibilities out there..