My son is 9 diagnosed ADHD w/ anxiety/depression. Adding in an anxiety med with his ADHD meds has absolutely helped him! Prozac was the first one we tried and it worked very well for his anxiety, but it interacted with his ADHD med negatively so we are now on Sertraline (Zoloft). One thing that happened with my son once we were on the anxiety meds is that his ADHD symptoms seemed to increase. That just told us that his ADHD isn’t being managed best by what he is on now. So, it was a good thing so we can address that part of it.
Good luck with whatever decision you make.