Chapter 8 is a quick chapter on planning the development of a blogging application. Chapter 9 is a concerete implementation if this application's Domain Model, specifically Entries and Authors. Its purpose is to write a Data Mapper using Zend_Db_Table in the background.
The book is a free resource, but if you like it and appreciate the work Padraic has put into you, you should consider donating to the cause. There's tons of great information in there - introductory topics, boostrapping, performance optimization and the creation of a simple blogging engine.