I think there are no predators that use clubs to hunt, maybe the closest thing is the mantis shrimp, but I think the killing factor are the waves produced and this happens in a very little size scale.

Some herbivore animals use blunt force for defense, examples like horses kicks with hoofs, the ankylosaurus' club tail and the pachycephalosaurus head, all them look like very harmful and effective attacks.

So, is it viable for a predator to use clubs as hunting tools or is there a reason why this hasn't evolved yet?

It can be considered any part of the body for terms of this question.