Strange rattle near alternator/ac compressor

[cumaru]

Hello everyone. We have a 2009 civic LX sedan 1.8 with 162k miles, which just started making a strange rattle coming from the area around the alternator and ac compressor. My theory is that it could be a bad tensioner, but we took it to a mechanic, who we've not used before, who recently looked at it said its coming from the compressor. I was wondering what others on this forum think. A video of the rattle sound is attached or it can be found at https://drive.google.com/file/d/1ObnOhYuRVhYJtXznFWmgHSQeGldQlTKV/view?usp=sharing.

I've looked at a number of videos involving compressor failures and none of them show this sound, so I'm skeptical of their diagnosis, but I'm no expert.

Assuming it is a bad compressor, is $1500 a reasonable cost for the repairs in TX?

Thanks in advance.