Which gods did pompeians worship?

I'd assume you mean before the eruption of Mt. Vesuvius. Being Romans, the Pompeians worshipped the Graeco-Romanesque Pantheion of Gods. The top God was Jupiter (Latin Iuppiter), and some of the others were Juno, Neptune, Ceres, Minerva, Mars, Apollo, Diana, Venus, Bacchus, Vulcan and Mercury.