As described in SPEC-3765, J1939 support is not enabled by default in the agl-service-can-low-level CAN binding, and is only enabled specifically for the qemu platforms when building via the full image build.  The restriction on enabling it by default comes from needing a >= 5.4 kernel to have J1939 support.  In Koi, currently only the RaspberryPi is using a kernel too old to have it, and this should hopefully be resolved soon with a fix for SPEC-3702.  Once that happens, flipping the default for J1939 support and potentially reverting changes done for SPEC-3765 should be investigated.