To the author’s knowledge, Cheristin cannot kill ear mites. There is no mention from the manufacturer regarding this purpose and no information on using Cheristin in an off-label manner for this can be found either.
Most topical flea products do not target ear mites with the exception of a couple that are absorbed systemically by the body. This includes Revolution for cats, Revolution Plus for cats, and Advantage Multi for cats (but not Advantage II for cats).