If your son is applying to next fall for 9/2016, most schools will only look at the tests taken in fall 2015
This means the only tests many of the schools will consider is 10/2015, 11/2015, 12/2015 and 1/2016. However there are always exceptions.
There's no SSAT lower and upper 成績. There is only one SSAT (for applying to high schools) and one SAT (for applying to colleges)
Some schools require a minimum TOEFL score to get an interview. Most high schools require TOEFL and NOT TOEFL junior scores.