Digging footer holes in crawl space
I don’t think a drill and auger will be of any use.
I did a job like yours many years ago, providing much of the grunt work for a much older, but more experienced workman.
Step one is to dig a trench in the crawl space deep enough to stand without stooping (much). The trench goes adjacent to (within reach of) the spots where you want the footings. Branch the trench as needed. Use a pick and shovel. To remove the tailings efficiently, fill a container about the size of a U.S. Mail bucket, drag it out and dump it. A pick and shovel can deal with hard soil and rocks. A drill and auger, not so much.
Step two is to dig out the sites where the footings will go using a pick and shovel, while standing in the trench.
Step three is to build forms for the footings.
Step four is to mix your concrete outside, fill buckets, carry via trench, and dump.
Safety note: if you need electricity down there, make sure to get it from a GFCI protected outlet.