Just a different point of view. If I read your posts correctly you say that he is a straight A student. He was "caught" stealing candy at 6 something in the morning. When you checked his computer history he was checking emails. He confesses to a lot of stuff, etc......
Hmmmmmm this kid doesn't seem too bad to me. Of course I am not the one living with him. One....he is doing great in school. This is an area where he really excels...don't cut his one outlet off by restricting after school activities that are related to the school. Two...it's obvious the boy has a sweet tooth. Is he being punished because "we" are now trying to get our kids to eat right which we didn't? If this is a continuing problem...don't bring candy into the home. Make him use an allowance to buy his own. Three.....At least it was his email and not a porn site. Four...A person who lies continuously normally doesn't confess to anything. It is always someone else's fault. Learning to accept fault is an adult trait, not a children's trait. It has to be learned over time. A child can accept responsibility for chores, etc...but will place the blame on others whenever possible. This is normal for the age.
Honestly, it sounds like to me you've got a pretty good kid. I'd take him in a minute.
My only other thought would be that because he is number 2 out of 7 your attention (and rightly so) is spent more with the younger siblings than with the older ones. Maybe he needs some one on one time with you or dad. It doesn't have to cost anything, but can be a walk in a park, a picnic, a trip to the mall where you just browse...anything.
By the other responses you've received I feel like I've missed something. But I think you should be very proud of this young man. He will turn into a fine young man...just give him some room to grow.