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.
Forty percent of the American opportunity credit is refundable for most taxpayers. However, if you were under age 24 at the end of 2014 and the conditions listed below apply to you, you cannot claim any part of the American opportunity credit as a refundable credit on your tax return.