Yep I was going to say you've no chance ------ as grades 9 to 11 don't exist!!!!!! The grades stop at 8.
Seriously though I would recommend a teacher - even if you only get a lesson say, once every 3 weeks. It's very easy to slip into bad habits, and learn something wrongly and not be aware that it's wrong. I agree with saxlover in that a teacher would be able to keep you on track, if you can find a teacher who you feel happy with. It may also be worth looking slightly further afield, especially if you only want more occasional input. And of courses, there's always all of us on here - mad maybe, but helpful too!!