  The atmospheres and accretion disks of planetary-mass and substellar
companions provide an unprecedented look into planet and moon formation
processes, most notably the frequency and lifetime of circumplanetary disks. In
our ongoing effort to leverage the extraordinary sensitivity of the
Spitzer/Infrared Array Camera (IRAC) at 3.6, 4.5, 5.8, and 8.0 $\mu$m to study
wide planetary-mass and substellar companions near the diffraction limit, we
present point-spread function (PSF) fitting photometry of archival Spitzer/IRAC
images for nine stars (G0 to M4+M7) in nearby star-forming regions or stellar
associations that host companions at separations of $\rho =
1.17^{\prime\prime}-12.33^{\prime\prime}$. We detect all system primaries in
all four IRAC channels and recover eight low-mass companions in at least one
IRAC channel for our sample, five of which have not been resolved previously in
IRAC images. We measure non-photospheric $[3.6]-[8.0]$ colors for four of the
system companions (DH Tau B, 2M0441 B, SR 12 c, ROXs 42B b), confirming or
discovering the presence of circumstellar or circum(sub)stellar disks. We
detect fluxes consistent with photospheric emission for four other companions
(AB Pic b, CHXR 73 b, 1RXS J1609 b, HD 203030 b) that are unlikely to host
disks. Combined with past detections of accretion or disk indicators, we
determine the global disk frequency of young ($<$15 Myr) wide companions with
masses near the deuterium-burning limit to be $56\%\pm12\%$.
