I would go for the babysitter option: the eye-gouging scene is pretty gross. When we saw it there were some older children in the audience who found it very hard to sit through - I think I would have done at that age too; the action bits are great but there is a lot of talking in between!
The eye gouging scene is the obvious issue but I would say that the sheer brutality of the fight scenes is more problematic. They are not fun, cartoonish fights that kids would enjoy, but extremely vicious and nasty scenes.
I watched the film sitting next to a family who had brought two young boys (about 7 & 9) who seemed unaffected by the violence, too me that was worrying.
We took my 8 year old despite my misgivings, my husband said it would be "fine".
My 8 year old is quite sensitive and I spent all the violent scenes with my hand clapped over her eyes! Luckily she hasn't had any nightmares but she really didn't enjoy it and I won't be taking her to another 12A film for a very long time.
You could try showing him Skyfall at home and then if he doesn't like it you can switch it off. And if he does like it then you could take him to Spectre. Most of my son's friends seem to have seen it. I think the violence is very cartoonish, but maybe that's just me - I love James Bond films. Have seen them all.
I think a definite no no for the kids. The fight scenes are nasty and I think a far cry from the marvel films. There's context too. Marvel films are by their very nature 'unreal'. The Daniel Craig bond films not.
And violence aside they are very talky.