how do I report a sale of unoccupied land and had a 9K gain?

To enter an investment sale -

Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Under Investment Income
On Stocks, Cryptocurrency, Mutual Funds, Bonds, Other, click the start or update button

Or enter investment sales in the Search box located in the upper right of the program screen. Click on Jump to investment sales

Using the online editions -

On the screen Did you have investment income in 2024? click on Yes

On the screen Let's import your tax info click on Enter a different way

On the screen OK, let's start with one investment type, select Other and Continue

On the screen Tell us more about this sale enter a Name and Continue

On the following screen select the type of investment sale on the dropdown What type of investment did you sell?

Continue with this section until it completes