Excellent news Farangatang, and sounds like the low grade is definitely worth investigating.
Kingscote I get the 8 vs 9 frustration too. My DS would feel the same and I am thankful that, although he did CIE History, it was the A*-G syllabus.
I am very sceptical that the 8/9 grades (for any board) will be a reliable discriminator at the top end when you consider how inaccurate the marking proves to be every year, and the number of remarks that come back with a changed grade, especially in essay subjects.