It is analyzed how dynamic Jahn-Teller coupling of an O- hole with the surrounding lattice in oxide perovskites affects the electron paramagnetic resonance of shallow O- defects. The predicted unusual resonance parameters are seen to be realized by experimentally identified O- defects in KTaO3. These centers thus manifest the properties of dynamic Jahn-Teller hole polarons in oxide perovskites. By varying the strength of the Jahn-Teller coupling, a continuous transition to the static Jahn-Teller case is modelled. The latter situation describes the properties of O- polarons identified previously in other oxide perovskites.