Sorry, but it doesn't make sense why a Tesla would apply the parking brake when the big battery dies, since the separate 12V battery would power the brake mechanism. If that 12V also happened to die at the same moment (highly unlikely), the parking brake would have been stuck in the released position, not applied.
And 9 hours? They could have called one of those tow trucks who haul away an illegally parked vehicle in a matter of seconds.