My son is 9.5. He has his moments, but not like has been described here. I'm hoping that doesn't start. He has enough issues as it is now.
I went back to work when he (he's my youngest) started kindergarten. It has never affected my kids directly because I work the same hours they are in school, they never miss me. On the other hand, there are definitely indirect effects because I end up worn out, grumpy, and tired of dealing with kids.