We don’t really know all the planets in our solar system
According to NASA, there are three other officially recognized dwarf planets around our sun (all in the Kuiper Belt, with Pluto) and maybe hundreds more that have yet to be discovered. And then there’s the mystery of Planet X— so far, it’s just hypothetical, but Caltech researchers think it might be the size of Neptune and follow an orbit that’s circling the sun beyond Pluto. The final count as of now, according to phys.org, is eight planets and five dwarf planets.
A toilet doesn’t flush the opposite way in the Southern hemisphere
There is some evidence for this idea: the Coriolis effect does mean that the rotation of the Earth causes hurricanes and cyclones to spin clockwise in the Northern Hemisphere and clockwise below the equator. But the amount of water in the toilet is too small to be influenced in the same way — it flows down the drain according to whatever forces guide it through the toilet. Any slight lack of symmetry in the drain, like build-up or crooked installation, will direct the water flow.