I know I'm too young to go and I'm ten times his age! LOL.

I took DS to see the first Pirates of the Carribean movie when he was 7 because people told me it would be fine for kids and because we actually knew someone in it. But as a family we don't watch TV and rarely go to movies and both he and I were on sensory overload for several hours afterwards--we had a hard time shaking the images and a hard time getting to sleep. DH was fine.

So I think it matters if your child is easily overwhelmed by sensory stimuli, if there are things in his life that allow him to be desensitized, if he is likely to get images "stuck" in his head etc.