Yes, it is a requirement if you are doing the Oracle9i track, and it must be with Oracle University. If you are upgrading from Oracle8i you do not need the course.
The best thing to do is read through the requirements on:
You may be able to find an exclusion that is relevant to you if you have already taken some exams.
If not then I'm afraid you stuck with it. I would suggest picking the course you'rte weakest at, or the cheapest if you don't think you need the training.