You can read Coppens assessment here.
The question nevertheless remains as to who these Nine Gods truly are. Indeed, “Nine Gods” are not just an ingredient of the Mayan culture. There were also Nine Gods in the ancient Egyptian religion, as well as many others (e.g. India). To the Egyptians, they were also known as the Nine Principles and they were directly linked with their Creator Deity, Atum.
Control over these Nine Principles was deemed to be instrumental in the successful rule of a Pharaoh: proper control over them meant that balance – linked with the deity Ma’at – was maintained and all was well with Egypt, the world and the universe. We can therefore see that The Nine in an Egyptian or Mayan setting, were closely related; in both instances, they determined the ruling of an era, whereby their consultation was of extreme importance to the success of the nation.