May be if you have got back links from at least 1000 PR7, 5000 PR6 sites then you can get a PR9. which is not possible i guess. so better not to jump to the roof. Try to move on step by step. Built a quality website, update the content regularly, make sure your site is useful for the users and there are alot of other factors that make your site Rank well in google and all other search engines.