> Earthworms do NOT eat roots or any other living plant materials.
Indeed you are right. That was just an other "pearl".

I do not know if they eat or not the roots but they definetely get my soil out of the pot and the roots will dry out in those holes

Here's a suggestion.
Try putting a layer of some fine mesh material, perhaps strong plastic netting or equivalent in galvanised wire, inside the bottom of your pots and across any entry holes.
This shouldn't change water retention but should stop anything larger than the mesh size from entering your pots. If the problem continues, at least you have an idea of the size of the culprit!

I've already done that , the soil is not getting out as much as it did but still from time to time I got some on few pots

This could be either because the worm eggs were there after transplanting or somehow got into the pot from above

If the soil is clean and the net is there I got none in the pot , but if only one can get in, there will be more than one since they can reproduce themselves being at the same time male/female as I remember well