General ACCAF5 or F9 next?

Hi All, I have just sat F7 today which went well, fingers crossed. I need to start preparing for my next sitting in the December 2017 sitting. Currently, I am sitting 1 exam per quarter as this suits me much better due to not being very good at exams and only wanting to focus on one. My question is - What should I sit next? F5 or F9? Or do i go against it and sit both in one sitting for December? I know people will comment saying some people are better at F5 than others etc due to job and background etc but in general, what are your thoughts? Any advice/comments are greatly appreciated. Thank you, Tom :-)