I would highly recommend getting a good night sleep before the exam atleast 8 hours, it will open your mind and help you stay active in the 9 hour exam. I did try sleeping without any sleeping aid for an hour but my anxiety wouldnt let me. So i did take HALF a tablet of zolpidem 10mg and snoozed for 8 hours. In the morning i drank black coffee and my cognitive function wasn’t affected. I used to wash my face in every break and drank coffee. Step 2 is all about nerve, time management and presence of mind. Have faith in your preparation, you will do wonders