1) I like the book The Explosive Child: A New Approach for Understanding and Parenting Easily Frustrated, Chronically-Inflexible Children, by Dr. Ross Green.
2) I like the books published by the Gesell Institute. They address developmental and personality issues in children for each year. Your Eight-Year-Old, by Louise Bates Ames, says this about eight-year-olds:
However, eight is also a time when the child begins to do a great deal of analyzing and evaluating, finding fault in himself and others--especially Mother. How do parents help an eight-year-old through this up-and-down age? What should parents expect in their relationships with the child and how can life in the family be made easier? What will the child's relationship with friends and siblings be like? In the successful tradition of the Gesell institute series, Your Eight-Year-Old is a well-researched, highly accessible guide.
3) In other words, you have a child suffering from ADHD/OCD/ODD, but he's also an eight-year-old boy, who gets to be evaluated on his own terms, with all the highs and lows his age-mates go through. Sometimes the phases kids go through are just normal -- but when a child has the disorders yours does, there might be an exaggerated quality to them. Or not.
Your son probably finds the world unpredictable, because his ADHD means that he doesn't act appropriately. He doesn't know if he's going to have a good day or a bad day, if he's going to do the right thing or say the right thing. He doesn't know of people will understand, or blame him. Most of the interactions with other people -- including you -- are full of negative emotions, through no one's fault. He might have the OCD symptoms -- and the ODD -- because they are ways to control a world that is otherwise unpredictable. I wonder if there are ways that you could give him a little more control -- in ways that are consistent with your parenting values. I'm not talking about letting him be disrespectful to you or others, that's not fair to you or to him. Because you love him, you have to help teach him how to act appropriately, so he won't be miserable. But I'm talking about little things -- like letting him choose how to redecorate his room, even if you hate the colors and you don't like Star Wars or superheroes or whatever. Let him choose one thing at each meal -- "pick a vegetable," "pick how you want the potatoes cooked," "do you want Shake and Bake chicken, or tacos for dinner?"
Some kids really do want to do the right thing, but they're so frustrated with the constant sense of failure they give up. Quick, immediate rewards for good behavior will help. With my older child -- my husband got a dollar's worth of foreign coins. Every time my son did something right, no matter how small, he got one. The dollar's worth of coins lasted us a week. So for four dollars a month....
I AM NOT A PROFESSIONAL -- just a mother who has two boys who suffered through some of the same issues. My children seem to have grown out of them, but when my youngest was three, when he got mad he would spread feces all through his room, on himself, on the walls, etc.
Good LUCK!