I have a 2009 Volvo XC70 and a grinding noise coming from the engine.

Yes the needle bearings are a common problem with si6 engines 2009 and older. If you repair it I would have the mechanic use 2010 or newer parts compatable with your engine. This issue should have been a recall. You will encounter a similar issue with a new engine from a car 2009 or older. Volvo wire harnesses are very touchy it is not uncommon to have electrical issues after an engine replacement. You also should keep in mind that you dont know the history of the replacement engine unless it is thoroughly gone over before it is installed. I would lean towards a repair using updated parts.