Kombre,
My DD took SCAT when she was in 2nd grade too. The only problem is that your school administrators may not know what SCAT is. Be prepared to educate them. If your ISD has district Gifted coordinator, make sure to get them involved as well.
Make sure that they know it's from John Hopkins CTY and 2 grades above level test. Clearly, your DS is excelling at 2 grades above level and he needs subject acceleration at least to 4th grade now. (In-class differentiation rarely works). I am pretty sure the school want to test on their own but he'll be fine.
