can you make turbotax not include the underpayment penalty?

Yes. The underpayment is based on the information you entered.  Removing the penalty does not mean the IRS will not penalize you.  If you prefer to be billed by the IRS,  here is how to enter the information in TurboTax Online:

1. Navigate to Federal > Other Tax Situations > Additional Tax Payments > Underpayment Penalties > Start or Revisit
2. Continue through the questions until you arrive at the screen Let the IRS Bill Me Later, and you can make your selection.

See also: Why am I getting an underpayment penalty if I'm getting a refund?