I feel for you. I’m a special Ed teacher. I teach a 3 3/4 self contained class. I don’t have any children but I know the age group. From what I’ve noticed it seems that 4th grade or 9 years old is the year kids start really being defiant with authority figures i.e. teachers, parents etc. It seems universal whether it’s a boy or girl, general ed or special Ed race, class etc. All kids seem to get rebellious at that age. Rolling eyes and saying oh my God!! for asking them to do anything. If your child has ODD I’m sure it’s really frustrating. Maybe taking away things like cell phone for periods of time? Idk but if positive reinforcement isn’t working maybe you should try punishment instead of reward. It’s like why shld he behave nothing bad will happen he won’t get a reward but he won’t get punished either so why not misbehave. If he gets some sort of punishment he may want to avoid that outcome again.