Since 2019 it is proposed that the hypothetical Planet IX may in fact be a primordial black hole. Black holes are being looked after differently than planets. You can look for a gravitational lens or for an accretion disc. However, the black hole theory doesn't seem to be taken serious by many.
Is there any ongoing search for such black hole rather than a planet, or are there any plans to look after a primordial black hole if the planet theory would get disproved?