Need advice on controlled offense for boys 11-12

In this situation, without knowing what type of offense you using now, I would say drills, drills, drills, drills!!!!! It doesn't sound like the offense, it sounds like confidence. I believe no matter which offense you run, if your players don't have confidendce in their ball handling ability, they won't make any offense work. There are numerous sites which you can use to look up drills that your team can use.
I love to use the drill "KNOCK OUT". This drill puts all of your team, each with a basketball, in the free-throw lane and they must maintain their dribble the entire time. While dribbling their ball they must try to knock the ball away from the other players without losing control of their ball or getting their ball batted away. Later on you can emphasize the out-of-bounds rule for the black line. This drill makes them switch hands, keep their head up, use their body to protect the ball etc... I showed this one to the high school coach in our area and he uses it now. It's a great basic drill and it's a friendly competition for the kids to see who can be the last one in.
Hope this helps.

Coach Rowland