The car is Subaru Impreza 2009, hatchback. It was scratched, and I am thinking of repairing it, but I am not sure if the scratch is deep or shallow. I am particularly concerned if this will cause any rust
Images: https://imgur.com/a/qd9e90e
Well that's pretty deep. You could try buffing it out and see but realize it's not going to rust because that's the bumper and that's made out of plastic
It looks like a scrape on your plastic bumper cover. It won't rust. There are videos on youtube you can search for showing how to repair that kind of damage.
Use white polishing compound on a damp rag to buff it out. I usually get a section of an old t-shirt, wet it and wring it out and wrap it around a dollar store chalkboard eraser, slather on the white polishing compound and rub it out, clean off the excess with a clean cloth and follow with a good coat of wax.
That's a really minor scuff on your plastic trim. Just buff it out
