  We report the direct imaging discovery of a low-mass companion to the nearby
accelerating A star, HIP 109427, with the Subaru Coronagraphic Extreme Adaptive
Optics (SCExAO) instrument coupled with the MKID Exoplanet Camera (MEC) and
CHARIS integral field spectrograph. CHARIS data reduced with reference star PSF
subtraction yield 1.1-2.4 $\mu$m spectra. MEC reveals the companion in $Y$ and
$J$ band at a comparable signal-to-noise ratio using stochastic speckle
discrimination, with no PSF subtraction techniques. Combined with complementary
follow-up $L_{\rm p}$ photometry from Keck/NIRC2, the SCExAO data favors a
spectral type, effective temperature, and luminosity of M4-M5.5, 3000-3200 $K$,
and $\log_{10}(L/L_{\rm \odot}) = -2.28^{+0.04}_{-0.04}$, respectively.
Relative astrometry of HIP 109427 B from SCExAO/CHARIS and Keck/NIRC2, and
complementary Gaia-Hipparcos absolute astrometry of the primary favor a
semimajor axis of $6.55^{+3.0}_{-0.48}$ au, an eccentricity of
$0.54^{+0.28}_{-0.15}$, an inclination of $66.7^{+8.5}_{-14}$ degrees, and a
dynamical mass of $0.280^{+0.18}_{-0.059}$ $M_{\odot}$. This work shows the
potential for extreme AO systems to utilize speckle statistics in addition to
widely-used post-processing methods to directly image faint companions to
nearby stars near the telescope diffraction limit.
