20 gallons for a 9 grams hognose is absolutely way too big, even a 6 quarts tub at that size is huge for them, so downsize is definitely in order.
Another thing to keep in mind is young hognose under 20 grams are not very good at taking the prey of the tongs, in my experience they do much better if you leave the prey on the tub floor.
Here is what I do with my hatchlings, I thaw their prey, push the bedding to leave an area without bedding, place the prey in the middle and usually the prey is gone by the morning.
I start tong feeding when they are 20 grams at which time they seem less skittish around the snake tongs.