Even wheels without spinout rims often have multiple mounting options on the hubs for changing the width of the wheel track. If the rim bolts to the hub, it’s likely that you can change the rear track by changing how the rim is mounted on the hub. The Ford 8N has something like eight possible rear track widths depending on how the hub’s dish faces and how the rim is mounted on it.My old Super 90 has the rims that have a spiral on them and the hub section clamps onto the spiral. All you have to do is loosen the clamps and roll forward or backwards and adjust the rear tire width. Surely someone makes an aftermarket set up like that for the M9000.
The pictures I’ve seen of the Kubota M9000 look like it has these kinds of rims, so @Roy14 might be able to gain the 5” just by changing how the rims are mounted.