You can download the trial version of the software thru the page linked below and then use your current serial number to activate it.
Be sure to follow the steps outlined in the Note: Very Important Instructions section on the download pages at this site and have cookies enabled in your browser or else the download will not work properly.
Photoshop/Premiere Elements 8: http://prodesigntools.com/direct-download-links-for-lightroom-3-and-photoshop-elements-8.h tml
As far as version 9 goes, if you never purchased it you shouldn't expect to be able to use it. If you check your Adobe account online you might be able to find whatever version you purchased identified there.