I Have a 320 with full guard and seeing steady swap usage increases in 9.109. These could be getting carried over to 9.2. Attached screen shot.
I checked my 9.108 and a 9.107 both on 220's. The 08 did have a steady swap increase, but the 07 does not. Both of the 220s only have the network protection package activated. So it looks like something with the IPS changes made from 07 to 08. Just a guess.