You are not a citizen until you are sworn in. If you are denied because of failure to pass the English or the civics test, you will be automatically rescheduled within 90 days. If you are not approved for some other reason, you may be given time to overcome the problem.
For 2009, the American Opportunity Credit--which is a variation of the Hope Credit--will be allowed for 4 years. For years before and after the new credit is allowed, the Hope credit is supposed to be for 2 years.
This could be a very useful student tax credit depending on what stage the taxpayer is currently at in their education.The American opportunity credit modifies the Hope Scholarship credit for any tax years beginning in 2009 through 2017.