Finding the ColdFusion Builder and ColdFusion 9 documentation on adobe site is always a bit difficult for me. To make a note for myself and for other CF developers who also found it difficult, let's go the Adobe ColdFusion 9 Family page and click Help and support link. In that page you will find both ColdFusion and ColdFusion Builder online help links under Getting Started & Help section.
Another way to reach the documentation page is through the ColdFusion Developer Center page as below.
So from now on keep remembering this simple ColdFusion support link URL and I'm sure you will not get into trouble on finding the online documentation for ColdFusion and Coldfusion Builder anymore.