I used to be a dumb cheater in high school. I was pretty smart but I still was cheating on things like dual credit courses at local colleges, and even AP exams. I ended up getting into a pretty good college. I felt pretty bad and since I've entered undergrad I haven't ever cheated, and I've been 100% honest. But I still feel pretty bad about what I did, and I'm scared it might hurt for graduate admissions. Is it possible that high school cheating can hurt me for grad admissions if it was in a college course? Also, if my high school diploma ever did get revoked, would my college degree get revoked as well?
Seems unlikely, but it might depend on where you are. In the US if you graduate from a program disciplinary actions aren't revealed except in extraordinary cases (court orders). You don't even mention whether you were disciplined.
If your transcript shows failed courses then you might be asked about it for university admissions, but for grad school the distant past remains buried.
If you aren't prone to cheating now, you will probably be fine. But if you are ever expelled from a program for dishonesty it would probably haunt you.