what does napoleon finally decide to do about the windmill and how is it explaine to the other animals?

Can you tell me which chapter? Napoleon decides a few things at various points in the novel.

ch9 the last time he try

All I can see in Chapter 9 is that Boxer is ill. He has been working overtime. Boxer’s split hoof, an injury from the battle, taxes him; still he will not let it deter him from rebuilding the windmill before he reaches retirement age. THat is pretty much it about the windmill in Chapter 9 unless I'm missing something.