" What is my tax status? Is it Resident, Dual or Non-Resident? Last year I filed taxes for year 2008 as Resident Alien?"-----> As you met your SPT test(>183 days) in 2009, you can file youir 2008 tax return either as a dual status filer filing a Form 1040 with a Form 1040NR as an attachment or as a resident alien( by filng your amended return 1040X in 2009). You will pay taxes at the state and federal level at the same tax rates as U.S. citizens. You can claim all the exemptions and credits which are available to U.S. citizens. You are also liable for taxes onyour world wide inocme as a resident alien. However, as your visa status is F1 now, your F-1 visa status makes you exempt from FICA deductions even though you filed as a resident alien.
What I mean is that the fact that you are filing Form 1040 in 2009 as a resident alien is irrelevent.
"Also second related query is can I use 1098-T to get Lifetime or Tuition credit?"---> Sorry, No; the American Opportunity credit applies to all four years of undergraduate college education;you cannot claim the AOC for your graduate school expenses. The AOC is only available for the first four years of your undergraduate education.
For further info. on AOC, please vist the IRS Web site;
American Opportunity Credit: Questions and Answers