It depends exactly what you mean by AOV. If you mean various render elements such as diffuse, specular, GI, depth, atmosphere, clouds, etc., then the answer is yes, in a future version of Terragen. "Render Elements" is a feature that I'm currently developing to be released in future. However, if you mean truly arbitrary output variables where you can assign custom attributes/variables to output elements (where the original term AOV came from), then I don't have a solution to that yet but it might be a possible feature in future.
Matt