I record my vocal tracks in mono, sometimes I want stereo vocal tracks. In another program, Vegas you duplicate the track and change the new track phase from left to right. There doesn't seem to be an option for this in Acid Pro 9, or maybe I'm missing something?
Your recordings are mono event clips. These sit on a stereo (or 5.1)audio track, which in turn sit in a stereo (or 5.1) project.
So, as I understand it, your mono event is processed to stereo at the track level without you needing to do anything. You can test this by panning the channel pan slider and it should pan whether you have a mono or stereo event.
If you want some deep dive on this look up "Signal Flow Diagram" in the in-application help. You'll see Channel Conversion happening in the first box underneath Audio Media - which is the audio event.