@cos231,
I do see what he means though... I get that it's hard to put everything pertinent in the original post, but each new post kind of puts a new spin on things.
From what you've said so far, I could still see things going a few ways.
Best-case scenario:
Two nine-year-old girls shared a bed on a sleepover. (I have an 8-yr-old girl, it's not unusual and I wouldn't find that worrisome.) The mom of one of the girls freaked out about it and forbade the girls from having contact outside of school. The girls are best friends and are sad about this. The other girl's dad decides to help out his daughter because he thinks the reason for the sudden cessation of contact is bogus and because she's sad, and he goes ahead and gets the kids together for lunch at McDonald's, etc. (You didn't respond if he was ferrying his own kids or if he wanted to meet the girl for one-on-one time.)
Worst-case scenario:
The dad is a pedophile and was using his daughters to help groom this girl for abuse. He is trying to have contact with her so he can pursue his interests in abusing her.
I don't know right now which is more likely, or if the truth lies at some point in between. If you're asking in general, I can see situations where it's perfectly legitimate for a non-parent to want contact with a child (and for a child to want contact with that non-parent). In this situation, I dunno. Some things sound weird for sure, and the dad seems to at the very least be going about this in a graceless way. But I can also see that things might be shaped in a certain way in your telling. So I dunno.