Those results match my sons! All grade 9 except for 7s in English Lang and Lit. In his case, they had "old school" English teachers who were obsessed with the classics and completely disengaged the pupils by the old fashioned method of analysing the shit out of Shakespeare, Dickens, and the Illyad! My son loved reading UNTIL he started secondary school and then the teaching turned him off and he literally never read another book, not even for fun! He only did the bare minimum he needed to do in English lessons and had no enthusiasm for it at all.
There was one bright point - in year 9, he got a younger teacher who had a completely different teaching attitude and he not only enjoyed it, but he got much higher marks, but sadly back to the oldies for years 10 and 11.
He never even read the set books for his GCSEs - he just waded through York notes to pick up the general themes/trends and characters, etc. To be honest, he was surprised to get 7s (as were we!). Such a shame that the way English is taught turns off so many kids! Now since leaving school, he's still not read a single book. Despite that, he's highly literate, sailed through Uni to get a First, and now works in the UK's biggest insurance firm, so ultimately hasn't hampered his education/profession, but as avid readers ourselves, myself and DH are really sad that he was turned off by the school/teachers.
Edit to add something else just remembered, his teacher continued to "teach" the background of the authors, despite admitting herself to the class that the background/context was no longer required to be known for the exams. She told them "she" thought it was important to teach the author background regardless of whether it was relevant for the exam! What a monumental waste of valuable teaching time! Like I say "old school", who sounded as if she couldn't be bothered teaching exam technique, mark scraping, etc., but wanted to continue teaching the way she'd always taught!