Fingerings 0-5 cover actual fingers (typically 1-5 for keyboard instruments and 0-4 for string instruments).
“Fingerings” 1-7 cover the number of slide positions on a trombone.
Combined 1, 2 and 3 (e.g. “12” and “13”) cover valve combinations on valved brass instruments.
8 and 9 are none of these things, so they’re not possible via the Fingering functionality.