What does Genesis 28:9 mean?
This concludes the thought begun the previous verse. Esau seems to have become newly aware that his marriage to two Canaanite wives displeased Isaac. Either Isaac had never communicated this to Esau before or after he married the Hittite women, or Esau had rebelled against his parents' wishes in marrying women from a tribe in the land of Canaan.Now Esau takes action to try to repair the damage and perhaps earn back his father's approval. He marries a third wife. This one, however, is not from one of the tribes of Canaan. She is also not from Rebekah's family in Mesopotamia. Instead, Esau marries the daughter of one of Abraham's other sons, Ishmael. Her name is Mahalath. It's likely Ishmael was dead by this time. So in saying Esau was "going to Ishmael," this passage likely means he went to the people of Ishmael. Some relationship between Ishmael's offspring and Isaac's family apparently still existed. It was now made official by this wedding.
We're not told if Esau's new marriage pleased Isaac or Rebekah, but it did not change his standing in the family. Esau still bore Isaac's near-curse. He was still not chosen to carry on the covenant promises of Abraham. In addition, the woman he married was from the daughter of another son not chosen to carry those covenant promises.