I posted last week that Gabriel would be back on the show. Given the information at the time, I was under the impression that he would be in the episode that was filming at that point, which was 9x21 King of the Damned. Apparently, we got to see everybody's favorite archangel a bit early. Now there are two possibilities, either this is his only appearance or they're foreshadowing his return later. It's entirely possible that they're going to bring him back for real later on. In fact, there's been talk among fans of the 2014!endverse happening, so we may even see Michael and Lucifer. Metatron's spell may have accidentally cast them out of the cage in hell.
I think they're reusing hotels again. This one looks like the one Sam and his girlfriend were staying at in season 8. I'm fairly certain they've run out of hotel sets and are just reusing them. They may have run out ages ago and I just haven't noticed until this season.
We should probably be very concerned about Metatron juicing up like this. Apparently, he's using the angel tablet to increase his own power. Even the archangels Raphael and Gabriel couldn't escape holy fire, and Metatron blows it out like it's nothing. Then he goes and erases angel warding. That stuff's supposed to angel-proof, an angel shouldn't be able to get rid of it. Then there's the spell he puts Cas under to trick him into following his plan. The guy's got some serious reality-warping mojo going on. This is probably going to spell trouble later on.
