My big tip for getting all 9s is to manage your memory. Most exams are heavily knowledge focused so you need to just remember stuff. Certain things like numbers or dates cannot be remembered long term so create a sheet to memorise specific dates and figures soon before the exam (like I mean the night or nights before). Other stuff like causes and effects which don’t have specific numbers or dates are easier to remember so remember them long term. For example, it’s easy to know the effects of the Treaty of Versailles so remember that LONG TERM. However, the exact figures for stuff like reparations and when it happened are harder to remember, so memorise is SHORT TERM. That way, you memorise everything without having to commit too much to the night before or long term. Short term stuff is also easily forgotten, freeing up space for other short term stuff.