The information shared above is insufficient to understand the exact issue you are experiencing. Would you mind elaborating on it a little more?
Were you upgrading your software from Acrobat Reader to Acrobat Pro, and installation got stuck at 90%, or it's the other way around that you were using the Acrobat Pro trial version and are now subscribed for it?
If you got stuck in the middle of any of these two situations, you could always start fresh by downloading the application again.
Run this cleaner tool to remove the existing installer and application’s file traces: