Hard drive compatible with iMac 2009 24"

The difficulty you will have with any off the shelf HD is beginning in 2009 Apple began using HD's that had heat sensors integrated into the HD. Most off the shelf HD do not have this. I would recommend contacting OWC (www.macsales.com) and they have a solution for this. There are software solutions, however I recommend getting the hardware solution as it will work and not over tax your fans or fan sensors. You can call them or they have on-line chats where they can recommend solutions.

If it was taped onto the old drive, yes it should be fine.