The basic plan looks to be oK, but, you need to prepare to fail, and to roll back to your current version
DP 8 introduces a totally new IDB, and this has caused a lot of problems. Many have been addressed in DP 8 patches, and, I woudl expect, many of these fixes were carried forward to DP 9. Still, I would not consider this version to be bullet-proof, so, before attempting an upgrade, make sure that you have your Internal Database and Configuration files withe backed up onto tape, or, tht you have stopped DP, made a copy of
Program Files -> Omniback -> db40
Program Files -> Omniback -> Config -> Server
(when you back up the IDB, thsi is what getes backed up)
If the upgrade is successful, you can delete these folders, although I would probably keep them around for a while
DP 8.1 introduced a new Licensing scheme. Once you have upgraded, you have 60-days to get the new licenses. Please review the Product Announcements Guide and the Installation and Licensing Guide for more information on how to get these new licenses