Hi, Please take what I am going to tell you with a grain of salt.
When dd was 10 the doc thought he might try her on adderall as Ritalin was getting in high dose range. DD was dx'd severe ADHD at age 3 had been on Ritalin with good success until age 10.
After about a week on the adderall I began to add up all the changes in dd. She became aggresive, insomniac, ocd-repetitive with odd little things, she began to wander at night as she could not sleep. She got a really odd affect in her personality ( she became very angry and could give looks that would KILL) I called the doc, after 21 days on the meds. I reported all of the personality changes and even brought in some of the things that she was writing at night when she was up.. scary stuff.
Doc took her off adderall and put her back on ritalin. All of the personality changes that came about when she was on the adderall subsided. whew!! She has always been a happy, non aggressive but EXTREMELY HYPERKINETIC kid. DD will be 13 in January. She cont's to be on a heavy dose of ritalin and ritalin sr.
Her school grades are excellent, her behavior the same as any other avg. 13 y/o girls

She does not fight me to take her meds yet.. I expect that to come in the next year or two. (eldest ds fought me tooth and nail when he got to h.s)
That being said, I have known many kids to have done very well on adderall. Different kids have different reactions to meds. I hope your son does better with his adderall. If not, no fear the doc will try something different which may work better.
BEST WISHES!!