You may also try and add more perlite or pumice in the soil, to allow faster drainage. Root ball of Crassula ovata is not big, so if it were mine, I would remove some of the soil and mix in perlite and pumice, so that when it rains again, the soil does not hold too much water.
I think the size of your container is okay, since that plant is quite big and matured already, anything smaller will just topple it, putting it in a bigger container I would not recommend either. But I would definitely do some changes with its soil.
