Probably brake rotors. They can be pretty loud. I've heard mine clicking with my window down at 130 mph at PIR down the front straight. Sound bounces off the cement wall. But it's not a single click, it's a continuous string of clicks, but that's due to some pretty hot brakes.
In any case, I hear plenty of clicks and pops on mine after I park in the garage, either rotors or exhaust. Can't tell from a video how loud it is, but it's probably nothing to worry about.