Discovery (Ancient 21th Century)
Planet Nine, truncated to P9, is a black hole that is responsible for the anomalous behaviours of objects orbiting far beyond the Kuiper belt, 6 times further than the heliopause of its parent star.
Being discovered the same way as Neptune and Pluto, the location of this black hole was deduced by using the anomalous belt of minor bodies and maths to figure out the necessary orbit and mass an object would need to reproduce the effects of the anomalabelt.
In 2079, when telescopes became powerful enough to observe tiny amounts of gravitational lensing, an expedition was sent out to explore P9, and become the first expedition to get close to a black hole. Knowledge of these mysterious objects expanded a massive amount. This mysterious beast is used to the Solar System, meaning that BHIP was not discovered here, and is not something to worry about.
In 2158, an attempt to put a moon around P9 failed, as the spin of the black hole would make any orbits nearby unstable. A scientific outpost existed on the edge of the hill sphere of this black hole, but required constant thruster burns to keep it in a stable orbit. In 2255, the station was evacuated and deorbited. It fell into the black hole, causing it to emit a short pulse of radiation.
Modern P9 (200th Millenium)
This astronomical body is not interesting enough to gather much attention, but it does have a museum of physical relics of the ancient world orbiting around it at a distance of 0.1 AU. This station uses modern hyper magneto-accelerated particle drives to keep itself in orbit, and is home to physical relics such as old chemical engines recovered many millennia ago from the seas of Earth.
This black hole also serves as a place where waste from the Sol system is dumped, thanks to being relatively close to the Sol system, cradle of our proud species.