My opinion is based on owning as 12K dump trailer, and a 2015 KX91 (7000ish lbs Kubota mini ex).
Yes you can do it. Not as fast as a 32k excavator of course but with a 24" bucket (if you have dirt and not tons of big rocks) it will be a full weekend job depending on how far you are moving the dirt and if you have someone to drive the truck/trailer.
I have a 12", 24", and a 36 smooth ditching bucket. For general digging a 24" is perfect, for hard rocky roil/ditching/ taking down trees the 12" bucket is great, cleaning ditches, moving gravel/mulch/etc the 36" works the best. Having a quick attach bucket system is worth every dollar if you buy a machine.
We have taken down a LOT of trees with the machine, cut a 60+ yard long, 10 yard wide bench in the side of a steep hillside for a pistol range, tons of trenches/ditches/etc and tons of other projects. Am I glad I bought a very slightly used machine - heck yes! Having a mini around is a BIG work saver!
