We study the charge and spin Seebeck effects in a spin-1 molecular junction as a function of temperature, applied magnetic field, and magnetic anisotropy () using Wilson's numerical renormalization group. A hard-axis magnetic anisotropy produces a large enhancement of the charge Seebeck coefficient () whose value only depends on the residual interaction between quasiparticles in the low-temperature Fermi-liquid regime. In the underscreened spin-1 Kondo regime, the high sensitivity of the system to magnetic fields makes it possible to observe a sizable value for the spin Seebeck coefficient even for magnetic fields much smaller than the Kondo temperature. Similar effects can be obtained in C junctions where the control parameter, instead of , is the gap between a singlet and a triplet molecular state.