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.
The Lifetime Learning Credit is not the only tax credit for educational expenses. There is also the American Opportunity Tax Credit (AOTC). You cannot claim both tax credits in the same year. While the AOTC has a higher maximum credit than the Lifetime Learning credit, it can only be claimed for four years of post-secondary education.