Installing 8.0.3 Employee/Manager SS over 9.0.0.5 version

We have multiple environments installed with various application versions in each.  Due to our testing environments we need to "flip flop" our Employee/Manager Self Service versions.

In other words we need to take an 9.0.0.5 version of EMSS and install it over an 8.0.3 version which I don't think will be an issue.  In addition, we need to install our 8.0.3 version over the 9.0.0.5 version and this is my concern. 

I am not worried about the bookmarks or Common Browser Library as I have those items accounted for. 

My concern is with installing the 8.0.3 webserver files over 9.0.0.5.  My other concern is with the Portal content.  It appears with 9.0.0.5 (or just the 9.0 versions of EMSS) portal content is now packaged with the application install and I am just not sure how this will impact it.

In short, is there an easy method to uninstall the 9.0.0.5 version of EMSS so I can just install 8.0.3 over it taking into account the Portal content and the EMSS install?  Thanks in advance.