> What evidence do you have for all the detailed
> record-keeping necessary to keep check of the
> passing of such long periods of time?
>
> In the historical world, we have some evidence of
> dates being noted - e.g., The Journal of
> Merer, which contained references that enabled
> present-day archaeologists to estimate that Khufu
> died in the spring of 2483 BC; and later documents
> such as the Anglo-Saxon Chronicle.
>
> But how were annals supposedly kept before the
> historical era?

First of all I don't hold that the "9000" yrs date is literally true, there are evidences that this date was not literally true such as the contradiction that Athens and Egypt were not around then, and that Egyptians are known for such exagerated dates. The true date seems to have been somewhere between 1500s to 1100s bc according to various scholars. The sinking was also an unstated amount of time after the war.

Oral memory has been sometimes proven to be remarkably accurate. Ancients were more able at this than modern literary people. The Druids are an example. Egyptian has 3 Hermes Set, Shu/Num, Thoth.

Some of the ancient peoples like the Egyptians especially had writing and scribes fairly early in ancient history. We know there are scripts and alphabets including Sumerian, Cuneiform, Aztec glyphs, Linear A/B, Hittite hieroglyphs, Elamite script, Indus Valley Script, Chinese glyphs, Rongorongo, Ogham, Runes, Sinaiatic script, Phoenician alphabet. There was also a script and writing in the Andean area. The protoliterate Jemdet Nasr period is early in Sumerian history. Atlantis is said to have had its own script in the Account. Scribes like the Hebrew biblical and DSS ones were experts. Egyptians also had some monumental records which were more lasting than papyrus records.
The word write first appears in the bible just after the stop Dophkah.
Some scholars show that the Medinet Habu inscription story of the Sea Peoples seemingly may match the Atlanteans in "Plato's" account.

For the accurate counting of the passing of time humans have long been using various means including astronomical to count the passing of time. Various high cultures had caledars. I think I remember reading that marks on Stone age bones or caves recorded keeping record of passing of days?

I would be interested to know more about the references in the Journal of Merer. But I am sure there will be some problem or unreliableness in the method because I am certain from other evidences that Khufu was really circa 1800s and matches Jacob in the bible.