Setting Frame Rate

There is a "Time Stretch" tool that might work to change playback speed. 

I started my video experience with Premiere Elements 9.  At the time it was released, the first consumer cameras that could shoot 1080p at 60 fps were coming on the market.  Premiere Elements 9 did not support them.  If memory serves, it was not until a standard called "AVCHD 2.0" arrived (that included 1080p at 60fps) that Premiere Elements supported it.

In version 9, you have to pick a project setting when you open a new project.  That is when the frame rate is set.  I recall one of the many choices did work, but it was marginal.   I stopped using version 9 six years ago, so I don't remember what the setting was. 

If you are going to edit 60fps footage on a consistent basis, I strongly recommend you update to the current version 15.   You no longer have to pick a project setting.  Instead, the setting that includes the frame rate is automatically matched to the first clip used in the project.  Editing footage with a specification adopted after the software was released should not be expected to work reliably!

Good luck with your projects!

Bill