My gf is Grade 9 piano....and she said he was pretty amazing for someone who is self taught.
highest grade is 8, i sat it when i was 13 years old
once you do grade 8 you go onto do diplomas for teaching grades. The Diplomas include AMusA, LMusA and FMusA
the guy made so many mistakes went off key, out of timing and missing notes that he tried to get. Yep he has fast fingers but that doesnt mean its hard. Some of the hardest songs to play are slow. Its all about timing accuracy and fingering. There are many songs at grade 5 etc that sound amazing and very hard but theyre not really as its only grade 5.