8yr old had fever of 99.5 early today. When he went to bed at 9p fever was gone. One hour later, I checked it axillary, it was 97.5. Is that normal?

Yes. 99.5 is actually considered at the high end of normal. Normal temperatures run between 97 - 99.5 with 98.6 as the middle of the bell curve. Also, night time is normally when or temps are at their highest, even when not ill.