Hi and welcome.
How off are his old WISC scores? The way I understand the application you need at least 2 out of 3 items: IQ test, Achievement test, portfolio items.
If his WISC scores do not meet the requirement but are not that far off, I would submit those along with the most recent Explore/ACT scores. I would then include portfolio items; in other words, assume that the IQ is not really counted and supplement with portfolio. My guess is that if you only submitted achievement testing you would be asked for more information.
AS for the recommendations, do you have any friend that comments on how smart your son is? What about somebody from a coop homeschooling group. Do you do homeschool entirely on your own? People have adviced using any type of coach. We used a family friend along with a teacher. You only need one but you can submit 2. I would bet that the religious instructor (at least one) has seen how unusual your DS is, it doesn't have to be something academic.
