If 9i certification is your goal you need to get some new books. There are substantial differences between 8 and 8i, and even more from 8i to 9i.
You have a choice here. You can use the Oracle manuals to get your information:
This is quite a dry and long-winded way of going about it. Alternatively you can buy some certification guides which more directly erlate to the OCP exams:
Remember, passing an exam and being good at your job are two different things. I like to think of OCP as the start of a learning process, not a goal in itself.