While many of the things in 8i will slowly be phased out in 9i and eventually 10i.
Going for 8i will help you get into a job(with some prior 8i experience) where migration into 9i and so on will help you greatly understand 9i. I think personally a lot of db's will move on to 9i by the end of 2003. So i think by getting your 8i by mid 2003 will be ok choice but any later will not really be that helpful as a lot of 9i jobs popping out will be rather discouraging.

So make your choice based on the how the industry is moving in your region. When I started with my 8i certification in april i thought i was a little late, and i wasn't wrong there(again rgion based opinion).

All the best and happy holidays to all my dbasupport fans and friends !!