I don't think there should be any axial or radial play in the shaft itself.. Not that you would be able to tell, as the shaft seals are too tight.
Rotational play can be caused by various things, worn sprocket? Chain tension? Or an issue with the clutch adjustment or gearbox.
Although you say the chain is fine, and clutch and gearbox faults are usually more noticeable in other ways. Slipping clutch is obvious, so is the gearbox crashing or jumping out of gear.