What a fun idea. The whole thing is kind of soft. A little closer in and with a less distracting shirt would help. I don't mind motion blur on the puppet but I think his face should be a bit more crisp.
I think this is a good idea, however, the lighting does not compliment the boy and the photograph is slightly out of focus. I would redo it with a faster shutter speed and add a little softer light in front of the boy. I would keep the strong light to the side of him so the shadows still cast on the wall.
Cropping a lot of the blank wall off the top would make this composition more dramatic.
It has a creepiness to it, I think from the lighting, that makes me think his sock puppet is telling him to do evil things.