REALLY? That's pretty bizarre. Even if she called home just before leaving the sleepover location, to tell her parents she was on her way home, why would they call police to report her missing, when she was at most 9 minutes behind schedule? I can see an unusually strict and protective parents maybe doing that, but it sure doesn't sound like Carlie's family fits into that category.
I haven't followed any details of the case, but quite possibly she was a lot more than 9 minutes late - maybe they'd been expecting her for awhile. It would seem to be beyond the normal procedures of any parent to call the police whenever someone is 9 minutes overdue!!
It was February 1, so it was nearly dark at 6PM. Carlie called home right about 6PM and said she was walking home. It should have taken 5 minutes, so she was already 21 minutes from the time she called, approximately.