Unless your system does not meet CDM+ 9.1 system requirements, you have no reason not to move up to CDM+ 9.1 now.
Afraid the "big" number change means a steep learning curve?
Don't worry! The changes in CDM+ that prompted a move from version 8 to version 9 are mostly "under the hood." If you're familiar with any version of CDM+ 8, you should move easily to working in CDM+ 9.1. Also, because all CDM+ training is conducted on the latest version of the software, you'll definitely want to upgrade prior to taking an Individual or Group Online Training course or having one of our staff conduct onsite training.