"ORACLE PL/SQL Language Pocket Reference" assumes that you are running at least ORACLE 8i and it covers ORACLE 9i as well (ORACLE 9i features are marked as such).
The content and coverage of the book is very good from my perspective. Even the more exotic features that I just can't remember, like e.g. the AUTHID stuff for PL/SQL procedures, are covered in this book. Even if you do not remember the exact keyword to look something up in the index, the book is still small enough to brose over every page in a couple of minutes to find your solution. All of the ORACLE 9i features (that I know of) are explained like e.g. "bulk binds" (cool PL/SQL performance feature).
The language and the new index are very good.
Even though this is a relatively small book, there are examples for almost every topic covered (although not big ones).
This is NOT the right book to learn PL/SQL and it will not teach you any SQL. If you want to learn PL/SQL, I recommend the other books (by the same authors) from O'Reilly that are all VERY good.