First, if the $9,400 came entirely from your basis in Roth IRA contributions, there is no need to apply the first-time homebuyer's exception to tax and penalty. Make sure that you click the Continue button on the page listing your Forms 1099-R and, when asked, update your basis in Roth IRA contributions as accurately as possible. You'll want to review your Roth IRA statements and Forms 5498 reporting your Roth IRA contributions.
If you've already distributed your basis in Roth IRA contributions and the $9,400 came from investment gains within the Roth IRA, the $9,400 applied to the purchase of a first home is a nontaxable distribution in 2021 only if you opened your first Roth IRA before 2017. Even so, TurboTax has a bug, introduced in the first release of 2020 TurboTax, that prevents it from accepting your entry of the amount of the distribution that was used for a first-home purchase. You can separately enter the amount as an exception to the 10% early-distribution penalty, but to make the distribution nontaxable you'll need you use the CD/download version of TurboTax in forms mode, override Form 8606 line 20 and enter the appropriate amount there; TurboTax presently has no other way to properly populate line 20. Doing an override will prevent you from e-filing.
