What little reference material I have on the 9mm Jap revolver cartridge is sparse. It appears that this cartridge requires a bullet of .350" diameter. I suppose that you could resize 90 grain .380 ACP cast bullets down if someone makes a bullet sizer in that diameter. It will obviously require a heavy roll crimp to keep the undersize bullet from moving inside the case during recoil.
A .38 Special case is about .010" longer than than the Japanese case, so case trimming is minimal. Conversely, a .38 Long Colt case would require no trimming at all. The rim diameters are the same as .38 Special/.38 Long Colt, but I don't know if there is any difference in the rim thicknesses. I guess if the Type 26 action will close and allow rotation without dragging then you're probably good to go.
Using .38 Special or .38 Long Colt cases will be a bit undersized in the Type 26 revolver so you will be likely to experience bulged or split cases as well as hard extraction effort unless you keep the cartridge reloads on the mild side.
Unfortunately, I have no reloading data. I would think that 3.0 grains of Unique powder behind a properly resized 90 grain cast bullet would be mild enough to start with. Trail Boss would probably be a better choice, but I have no intuitive feel for how much to use as I have no working experince with it.
In any event, proceed slowly and be careful.
-Lee