There aren't many electronic devices today that use a 9 volt battery so, if you neglected to put one in your kit, you're more likely to have an AA battery in some of your equipment (e.g. flashlight, headlamp, lantern, radio) in which case this trick...

Starting fire using gum wrapper and battery - GIF

is the way to go.

I can't tell for sure whether the gray stuff in the video is steel wool or dryer lint. Regardless, the latter is good for fire starting; I've ignited it with a small magnifying lens.