Can I file a Form 9465 (Installment Agreement Request) in TurboTax?
Yes, but only if you haven't filed your return yet.
To get to Form 9465, go through the File section of TurboTax until you reach the screen How do you want to pay your federal taxes? (You won't see this screen if you owe $0 or are getting a refund.)
Then, select the installment payment plan option, click Continue, and follow the onscreen instructions.