I have a 2009 jaguar xf premium luxury looking to replace oxygen o2sensor need some insight about this project

 

There are usually 2x O2 sensors per bank, one each for pre-cat and post-cat.

Which engine does it have?

They are relatively easy to do, you just need to prop the car up to get access to the cats, you might need to remove the engine guard to get access to them easily. You either need a 22mm O2 socket or suitable spanner to remove them but space is a bit tight so can be fiddly. If its been in there a while they might be tough to move and you need to be careful not to sheer it off or rip up the thread, because then you need to remove the cat to repair. If you can't budge it with a bit of levering try running the engine for a short while until they are warm, but not too hot otherwise you are going to burn yourself trying to get them out. They are connected to the wiring harness just a short distance from the cats.