I would put your containers on supports to keep them off the soil. Your tomatoes are likely to grow out of the drainage holes and into the soil, otherwise. You don't want to convert your container into a raised bed. Al

I can't put them on supports on her yard. So I take it that the worms would probably get into the container if I didn't place them on supports above the ground?

I used what I had around the house for supports, in my case 2 lengths of 2" diameter pvc pipes. Not very noticeable and just enough to keep them off the ground.
A couple of blocks hidden under the containers would work and not be visable.

Just my 2 cents, good luck with the tomatoes!

Larry