TurboTax is requiring me to enter a value in Box 9a of the 1099-R screen, but my paper 1099-R has no value in Box 9a?

If you don't have a value in your box 9a on Form 1099-R then leave it blank and continue. 

If this doesn't work try to delete and renter your Form 1099-R:

1. Click "Wages & Income" (under Federal) on the left
2. Scroll down and click "Show more" next to "Retirement Plans and Social Security"
3. Scroll down and click "Edit" next to "IRA, 401(k), Pension Plan (1099-R)"
4. Click the "delete/trash can"  and then click "Add another Form 1099-R"