  We present follow-up SCExAO/CHARIS $H$ and $K$-band (R $\sim$ 70)
high-contrast integral field spectroscopy and Keck/NIRC2 photometry of
directly-imaged brown dwarf companion HD 33632 Ab and new radial-velocity data
for the system from the SOPHIE spectrograph, complemented by Hipparcos and Gaia
astrometry. These data enable more robust spectral characterization compared to
lower-resolution spectra from the discovery paper and more than double the
available astrometric and radial-velocity baseline. HD 33632 Ab's spectrum is
well reproduced by a field L8.5--L9.5 dwarf. Using the Exo-REM atmosphere
models, we derive a best-fit temperature, surface gravity and radius of $T_{\rm
eff}$ = 1250 $K$, log(g) = 5, and $R$ = 0.97 $R_{\rm J}$ and a solar C/O ratio.
Adding the SOPHIE radial-velocity data enables far tighter constraints on the
companion's orbital properties (e.g. $i$=${46.6}_{-5.7}^{+2.9}$$^{o}$) and
dynamical mass (${51.7}_{-2.5}^{+2.6}$$M_{\rm J}$) than derived from imaging
data and \textit{Gaia} eDR3 astrometry data alone. HD 33632 Ab should be a
prime target for multi-band imaging and spectroscopy with the James Webb Space
Telescope and the Roman Space Telescope's Coronagraphic Instrument, shedding
detailed light on HD 33632 Ab's clouds and chemistry and providing a key
reference point for understanding young exoplanet atmospheres.
