We report hyperfine-resolved scalar polarizabilities for cesium’s 8s S1/2 and 9s S1/2 states using resonant two-photon spectroscopy in both an effusive beam and a vapor cell. Electric-field strengths are measured in situ, and the frequency scale is directly referenced to the ground-state hyperfine splitting of atomic rubidium. The measured 8s S1/2 scalar polarizability is 38 370± 380a 0 , which...