During upgrade from CA UIM 8.5.1 to 9.0.2, UMP and UR is installed in the Primary hub instead of the UMP server.
Release : 9.0.2
Component : UIM - UMP
First please follow,
UMP installation defaults to using Primary hub robot not the UMP robot
https://knowledge.broadcom.com/external/article/132984/ump-installation-defaults-to-using-prima.html
Second, please make sure that the UMP robot is under the Primary Hub. In other words, the UMP robot machine reports to the Primary as its parent hub.
Please ensure you've also uninstalled UR from the Primary as per the Help doc before trying to reinstall UMP.