It's likely that the nut that holds the steering wheel on is indeed loose, I've seen this a few times on these models. You have to remove the airbag, and it takes a 4" long, #30 Torx tool to remove the bolts. It's fairly easy once you do it, you just need the right tool and you need to be very careful you don't cross-thread the bolts when installing them. My suggestion is that you get a subscription from AllDataDIY.com and it will have the information from Volvo on exactly how to remove the airbag. The subscription is much less that having someone do it and you will get the Volvo factory info!