I had no install problems with 9.1. After starting the first collection it failed multiple time with "Error occurred while collecting inventory data. You will need to close and rerun the wizard." It finally finished the collection after several days of running and having to restart collection.
After it finished collection it failed the assessment process. Tried that 3 times and it failed every time.
I have uninstalled 9.1 and gone back to 8.0. That was the best version of MAP to date and runs in a relative short time without issues. I saw in the 9.1 readme that you asked numerous bugs to leave. They did not all go.
Mike Y.