Make sure you know your set works inside out. For example, play a set work and talk to yourself about all the key features as they are played or just listen and read through your score (maybe follow different lines each time).
A good way of revising (I also used this for my A-Level) is to make a grid with the headings: melody, harmony+tonality, structure/form, instrumentation, dynamics, rhythm+metre+tempo, and texture.
In one colour, write down everything you can remember about that set work without listening to it or using the score.
Then listen to the set work and, in another colour, add things in as you hear them while listening (no score).
Then finally, open your score and get any class notes or notes from the exam board (e.g. the Pearson Edexcel notes) and add them into the sections in a third colour.
To wrap it all up, listen to the set work and try to listen out for the things you didn't know off the top your head in the first go.
If you do that for all your set works a 9 is very much achievable. Good luck!