In your stop_times.txt file, each row has an extra comma at the end. You have 9 headers, but effectively 10 columns of data, even though the last column (after the final comma) has nothing in it.
I'm not sure why my tool isn't handling that situation, but I will update it so it doesn't fail.
A quick and simple fix for you is to just add a dummy column name in your stop_times.txt file:
trip_id,arrival_time,departure_time,stop_id,stop_sequence,stop_headsign,pickup_type,drop_off_type,shape_dist_traveled,junk
The tool will succeed and will ignore the junk column.