In chapters 8 and 9 of "Animal Farm," the following plot events occur:
- The pigs reduce the animals’ rations yet again.
- The dogs attack Snowball and chase him away from the farm. (This occurred earlier, in Chapter 5, but it is relevant to the storyline.)
- The pigs have Boxer killed, but they lie about him dying in the hospital.
- The animals rebuild the windmill with walls twice as thick as before.
- The pigs start drinking whiskey to excess and wearing green ribbons.
- Animal Farm is declared a republic, and Napoleon is elected president.
The event about the howling thunderstorm destroying the windmill does not occur in these chapters; rather, the windmill is destroyed during a battle with the humans in Chapter 8.
So, the checked events from your list relevant to Chapters 8 and 9 would include the first, third, fourth, fifth, and sixth items.