Cepheus
As he was once the mythical King of ancient Ethiopia, Cepheus holds court in the night skies sat in his throne, always circling the North Star close by to his wife Cassiopeia. His constellation can be recognisable as the simple western house design, with 4 walls and a pointed roof. Or it could be viewed as a dreidel (spinning top). But included in the constellation are two sets of connecting stars, joined at the exposed corners. These can be somewhat harder to observe with a naked eye in light-polluted areas.
Greek/Roman legend
The constellation represents Cepheus, the king of Ethiopia and Cassiopeia’s husband in Greek mythology. Zeus placed him in the sky after his tragic death because he was descended from one of Zeus’ loves, the nymph Io. Cepheus ruled not the modern-day Ethiopia, but the stretch of land between the southeastern Mediterranean and the Red Sea, the area that contains parts of the modern-day Egypt, Israel and Jordan.
Cepheus’ wife Cassiopeia was a very vain woman. Once, she boasted that she was more beautiful than the Nereids (sea nymphs, one of them the wife of the sea god Poseidon), which angered the nymphs and Poseidon, who then sent a sea monster, represented by the constellation Cetus, to ravage Cepheus’ land.
Cepheus turned to an oracle for advice on how to prevent utter disaster and the oracle told him that the only way to appease Poseidon was to sacrifice his daughter Andromeda to the monster.
Desperate, Cepheus and Cassiopeia did this, leaving their daughter chained to the rock for Cetus to find. Luckily, the hero Perseus found the princess first, rescued her and killed the monster. Later, he married Andromeda.
Perseus and Andromeda were celebrating their wedding when Phineus, Cepheus’ brother, turned up, claiming that she had been promised to him first. Phineus and his followers asked that Andromeda be turned over to them, but Cepheus refused them and there was a fight. Perseus tried to fight off all his opponents, but he was sorely outnumbered and had to use the head of Medusa to turn his enemies into stone. Unfortunately, the king and queen did not look away from the Gorgon’s head in time and were turned to stone, too.
https://www.constellation-guide.com/constellation-list/cepheus-constellation/
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Although his name is most well-known in connection with his daughter, Cepheus was placed in the sky of his own right: He voyaged as an Argonaut with Jason on the quest for the Golden Fleece.
Conclusion
With Cepheus being mainly recognised for his relation to his wife and daughter, Andromeda and her legend, I don't really see all too much of a reason for his to be placed in what could be considered an important location in the sky. It could be that he was revered for his voyage on the quest for the golden fleece or that he was loved by Zeus so much so to be placed in the sky by his wife after his death. Either way, I feel it would be worth looking into and understand who Zeus was in the night sky if there is a connection between the Roman god Jupiter and Zeus and where the other planets come into play. I could personally understand making their main god the planet Jupiter as it was incredibly bright in the sky when stargazing myself, and even after 20 minutes observing, Jupiter can clearly be seen making its way through the constellations.