i thought i can access to omen island once i have completed the pieces but it show 0/9 completed. Did i miss anything?

You're sure you have [item=uncharted land map piece ] 1-9, and not the treasure map? And you've gone to the Omen Islands page in the Treasure Map game?

PS: Noticed you have two threads about this topic. In the future don't create duplicate threads about the same topic when it's still on the first page.