How do I use the raw editor in PSE9 on a jpeg file?
In windows, in the editor choose File>Open As. On a mac in the editor go to file>Open, select the file you want, then choose Camera Raw from the format menu before you click the Open button.
Browse this post for more info - http://blogs.adobe.com/pselements/open-jpeg-files-in-adobe-camera-raw- in-photoshop-elements