Wow! Those are truly amazing scores. You may want to ask the school to do achievement testing. That way you can get the required achievement test data for DYS and the administration will understand that your son is way beyond K.
Either way you may want him to take the PS end of 1st+ grade test. I would think 2nd and up would be even better.
I would look into the gt school and also see what your PS has to offer. It may be really difficult to find a good fit for such a gifted boy. Chances are the gt school is geared more towards MG children and one grade skip in PS won't solve anything.
You definitely want to apply to DYS. The long application and the additional testing or portfolio is worth it.
Good luck
