Yep, that should work fine. Lots of folks swap eggs and new hatched chicks back and forth between a broody and incubator. Luckily hens can't keep track of time and they don't know what their chicks are supposed to look like! LOL
I would make sure the new eggs are warmed to 'room temp' at least before you swap them out, so the hen doesn't get a shock of cool eggs all at once though. So after the 9 eggs sit to settle for you then place them in a room with decent temp for a few hours to let them come up to temp.
Again thanks for the great advice.
I will switch them on Sat evening.