1997 9000 Aero Droning/Humming that increases with speed

Hi Eric, My 97 Saab 9000 Aero (130,000 miles) is making a droning/humming noise when driving that increases with speed – everything else is totally normal. My first thought was a bad wheel bearing, so I jacked it up and yanked the wheels around. No play in either of them.

So then I gave all the suspension components a good yank and found that one of the outer CV shafts has lateral play in it (everything else was completely tight).

What does this mean? Could it be that just the wheel hub nut is loose? Could it still be a bad wheel bearing? Or do I need to replace the CV shaft?

There is no clicking noise when the wheels turn, which makes me think that the CV joint at the end of the shaft is fine.