Hi,
I have a son with ODD, he's 10. For 5 years I knew something was 'off' with him and realized it's beyond anyone's control. We are in the very early stages of having him evaluated for this and ADD, since they say ODD is never a single diagnosis, it usually involves another disorder as well with symptoms of another, comorbidity is the term they use.
I can only tell you and you probably know and have experienced first hand how difficult these kids can be with the defiance, oppositionality and anger, they're always blameless, never their fault, they don't fear authority of any kind, they are disruptive, intentionally annoy other people, don't care about consequences, etc...
Our neurologist finds that individual counseling does not usually help a child with this (I tend to agree) but plenty can help the parents learn to deal with the kids.
I can't give you any advice, I just wanted to let you know you are not alone. It's never easy and I know my son is predictable at times and unpredictable at other times, you never know how your day will go visiting someone or the issues that will arise with them.
Are you having him eval'd by a professional?