Ok, here goes.
First thing is to go to my website, and download the updated rse files for any manufacturer you are flying/are interested in. The link follows, and if asked the username and password are both guest.
https://www.rocketryfiles.com/?p=home&d=FlightSimulation/MotorFiles/
Save the files to the c:\program files (x86)\Rocksim 9\data
My files are the most current going, and are named with the date included. No need to change the name.
Open Rocksim.
Click File, and then Reload Engine Data
You will see the following window open:
Make sure the Engine data path = C:\Program Files (x86)\RockSim 9\Data
Remove the old motor files on the right, and add the new ones from the left.
Click OK, and you should be done.