"Mi papá es un poeta."
Translation:My dad is a poet.
You are correct, but what you are doing is called "literally translating". Papá and padre are the essentially the same word. They are the same thing, but one is informal, one is formal. For example, In English, we do the same "Dad and Father" these are the SAME WORD. Just to clarify.
Just the same, for the most accurate translation (and I am not talking about literal translation, here), formal words get translated into formal words, and the diminitive into the diminitive. Therefore, padre beomes father, and papâ becomes, dad. And vice versa.