Moving 2.35:1 crop in 16:9 video, and outputting 2.35:1 video?

Being amateur, my framing in a recent shoot wasn't optimal at all times. Somewhat luckily, I'm using a DSLR that has 2.35:1 guidelines, but records 16:9. So I should have some leeway in editing, right? I'd like to move a 2:35:1 crop within a 16:9 picture. For example, in one part of a scene, I'm fine with the typical 2.35:1 crop, an even number of pixels off the top and bottom. But in another part of the scene, I'd prefer, for example, to take all the pixels from the bottom. In yet another scene, I'd like the crop to move up the screen. Is this stuff possible in FCPX? And can I then export the 16:9 movie to a 2.35:1 movie along the crops I manipulated?

system info:

MBP mid 2015 15"

OSX 10.13

FCPX Trial, 10.3.4