The main idea/important event in Gn 9 is that God asked Noah and his son to multiply the population in any way they can. The first thing that happened is that God blessed Noah and his sons, and he made them able to be fertile and multiply in any way possible. Next God made a covenant with Noah and his sons about all the creatures that are made shall not be destroyed by the water and there will not be another flood to destroy anything again. Finally Noah became drunk and was naked, two of his sons Shem and Japheth covered him up without looking. When Noah woke up he cursed Canaan and blessed the other two. Noah ended up living a really long life. A life lesson that we can learn from this passage is that the blessing of God was really important.
"God blessed Noah and his sons and said to them: Be fertile and multiply and fill the earth" (Gn 9:1).
"God said to Noah and to his sons with him: See, I am now establishing my covenant with you and your descendants after you" (Gn 9:8-9)
"Shem and Japeth, however , took a robe, and holding it on their shoulders, they walked backwards and covered their fathers nakedness" (Gn 9:23).