I have 2 columns in number that need to be military time format. When 09:00 is entered it changes to 9:00

Hi MT,

Enter the times as text. You can either format the columns as text, or type an apostrophe to "force" text format. For example, type '09:00

Numbers will recognise the text as valid times.

Regards,

Ian.

You can format the cell(s) to display it as you want. See the following: Numbers for Mac: Format Numbers table cells to display different types of data

Set the format to Date & Time and then choose the time format.