First of all get your dates right before you begin to bring false statements about history...
Abraham was not 900 BC...even Moses was more than 900 BC! LOL!!!
Abraham was 2000 BC...at around the same time of the Ziggurat Tower, check your dates. Secondly, Moses was 1250 BC...way before Nebuchadnezzar.
Thirdly, Babel does not mean ladder of the gods. It means "confusion" or "division". Why, because it was there that the languages were "confused" or "divided". Remember the book of Genesis is not the only historic account of this event. Mesapotamia and Babylonian artifacts and writings speak of this event. As well as many other artifacts and writings of other ancient nations speak of this event as well.
Nebuchadnezzar was WAY after this and WAY after Moses died. In Nebuchadnezzar's Babylon time was where the Torah AND the Prophets, Psalms and most of the Old Testament was taken from tablets and translated into SCROLLS. Israel and Judaism, if you will, as well as all the creation, law, and proverbs and the rest of the Hebrew culture was already there.
The Babylonians conquered and took over Israel at around 700 BC when the King of Israel was Hosea. Moses was way before they even had there first king. Hello!
The Babylon you are mistaking is the Babylon of Nimrod who founded Babylon, before Hamurabi...1750 BC. Nimrod was alive at the same time that Noah was alive. Nimrod was actually Noah's great-grand son. Abraham was living in Ur of the Chaldeans of "that" time. And Abraham was of the lineage of Shem who was the son of Noah.
Nimrod, the founder of Babylon, which was first Shinar before the confusion and divisions of the people...came from Ham, the son of Noah who was immoral and rebellious. He became the first King. He developed the Pagan Religion where he was deified as the God, Incarnate. From there the pagan traditions of Babylon.
Noah, taught his children to follow God and he taught them to read the stars and to wait for a Messiah promised to liberate and save mankind. Nimrod claimed to be this Messiah. He died of course and his wife claimed that his son was his reincarnation...and so goes the religion...