Yes you can create your own content using other applications.
I wouldn't say you need programming experience, but you should
be prepared to use "configuration" skills as you will need to edit and tune certain files that contain info that your weapons and models may need. You will need to create animation for your characters and rig skeletons for them.
While specifics may differ, the basic steps to creating your content are the same between the X9 and X10 versions of FPSC.
"Everyone has a plan 'till they get punched in the mouth" -- Mike Tyson