If he were my son, I would focus simply on good husbandry to begin with. He is nine. His love may be snakes this year, but tropical fish next year.
Also, as a breeder you are dealing with lives. Ethically, the lives come before the money - that holds if you are raising meat chickens for the customer's freezer, or English Mastiffs as pets.
This is not to say that I wouldn't choose a morph with potential; a good morph will keep your son interested and forward thinking with a goal...just that the money side isn't everything.