For simplicity in the learning curve put a scope on it right away. Iron sights are tough to learn to use accurately at any length of distance. If you want him to learn iron sights get him into CMP or 4H shooting groups.

I'm a hunter safety instructor here also and I always suggest scopes. Though I would prefer lower powered. IE 4X is plenty to start with. And I'd prefer fixed so they can't crank it to 9x and then not find a deer up close when the moment of truth comes.

Jeff