I bought a 10k trailer for my CK30. By the time you add one 3pt implement to the tractor or filled tires to even a CK30 you will be overloading a 7000lb trailer. Your 5400 lb machine + loader puts you overweight on a 7000 lb trailer before you can even get any work done. You do realize that you are supposed to have something on the rear when doing loader work right?
If anything, I find the Kioti specs lower than actual but I also know that a full sized case 580 backhoe is up near 10,000# so 9000 is way too high for your machine.
You'll want a 10k or larger trailer. The quality is almost always better, the build of the trailer is MUCH stouter, and you will have a margin of safety vs. the ragged edge of death every time you tow. Then there is the whole liability thing where any wreck be it fender bender or killing a family will be your fault because you were "overloaded" and so guilty.