I have been diagnosed with ADD and with CF, ADD (attention deficit disorder) when I was in 3rd grade and CF at 5 months. These two things are totally unrelaited. Although if you are concerned that this child is acting out, or being disruptive, it might stem from the fact he feels like he dosen't fit in. It's hard to cope at that age being different from all the other kids can really be upsetting. By 9 years old you understand you are different but don't really understand why or how. I was lucky enough to be an only child so to me having CF at home was totally normal getting chest PT and meds everyday, but if he's not it might be more obvious to him that he's different. Also at 9 years old, you more fear CF because you don't understand it, not because of what the real effects are on your body. Like the girl above me (11yrs old) she thinks she can die at any second, CF is not an acute illness, but thoughts like that can cause anxiety and make children more upset about the challenges they face. Make sure to work with the parents in getting him tested for ADD, it's a test to measure his brain wave patterns, and make sure that he isn't isolated in your class room. Make sure to do your research, he really might just be a troubled kid, people love to jump on ADD as the answer because it's the easy way out. Best of luck.