Here is my method..
In L9... locate and click on the media icon on the far right hand side of the screen
Select the Browser tab.
Browse to the L7 project
Double click on the project and the various tracks of the project will be displayed.
Select the track and check off what exactly from the track you wish to import into your L9 project
Click on "ADD" at the bottom righthand corner
"Rinse and repeat!"
Update: Or what Steve said..................