I figure he was just lying. And he's not very good at it.
Basically, his story is, "F9/11 isn't playing in my area, but my kid and his friends wanted to see it, so I took them to see it."
It's like he started out complaining (probably falsely) that he couldn't see the movie, then decided that he'd look cool if he claimed he conned people into letting him brainwash their kids, so he switched to that lie without ever deleting his first lie.
Of course, the "fact" that the kids immediately turned into raving lefties is just too perfect. And the "waiver" part doesn't pass the smell test. Would anyone asked to sign such a waiver not smell a rat?
Some people are so desperate to impress others that they tell lies that are both transparent and self-contradictory.