I have a 16 year old son as well who is “off the charts” as far as his ADHD is concerned. I’ve not had an issue with truancy or theft, but I recently found out he’s tried pot to calm his angst after his meds wear off. I believe if it were me, and my son was doing those things, I would take him to the psych who diagnosed him for some 1:1 sessions. Since he’s dealt with it for so long, probably in trouble a lot in elementary and middle school, probably has a bad taste in his mouth for authority figures, because they probably just punished him instead of trying to help.
There are a ton of articles that have helped me over the years as my son was about 11 when he was diagnosed… So you are definitely in the right place for ideas and assistance. Keep your chin up.