We present stellar and planetary properties for 1305 Kepler Objects of Interest (KOIs) hosting 2025 planet candidates observed as part of the California-Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with isochrone modeling to estimate stellar masses, radii, and ages. Stellar radii are constrained to 9%, compared to typically 42% when only photometric constraints are used. Stellar masses are constrained to 5%, and ages are constrained to a factor of two. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetary radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 11%. We also leverage improved knowledge in stellar effective temperature to recompute incident stellar fluxes for the planets, now accurate to 19%, compared to a factor of two when derived from photometry.