You don't mention which camera system this is for but cursory google search indicates this to be for Pentax. If this is correct you will be looking for a M42 or Pentax screw mount adapter of which there are plenty to be found from Chinese manufacturers on ebay.

Before spending dollars on a mount, find out if you need a flanged or non-flanged adapter because if you get the wrong one you won't be able to set your aperture properly with the wrong adapter. This is the case with the Carl Zeiss Jena 135mm f/3.5, which requires a non-flanged M42 adapter. Ask the seller on ebay if unsure.

Also whether the lens will fit depends if there's anything at the rear which would smash into the mirror. Usually the Canon crop sensors have little problem with clearance so you should be fine but do check the lens by focusing to see if anything protrudes at the bottom.

As to whether it's a waste of time well it depends on the lens. If the lens has issues and you're not getting anything remotely useful or great then it's a waste of time. There's some gems to be had out of them but to be very honest I haven't heard Kiron mentioned in the same breath as Zeiss, Mamiya, Olympus OM or Contax Yashica. Incidentally these brand of old lenses are the costlier ones found on ebay to the point that it might be cheaper and less hassle to get modern day equivalents.

p.s. Do mention which camera system it is for and I will update the answer accordingly.