I am a grad student and won a fellowship. I filled out a w-9, but have not received a tax form, like a 1099. The amount is not on my 1098t form. How do I pay taxes on it?

You would enter the income in the Education section in Deductions and Credits tab.  Select Expenses and Scholarships.   There is a field in this section to to enter Scholarship, grant and fellowship income not reported on a form W-2 or 1098T.