Sizing for 361s (Joker 1 GTs)?

Hi I was wondering if anyone with joker 1 gts could help me clarify their sizing, since it seems different from other brands. I currently use Lebron 21s size 10.5 US, which I have a little bit of wiggle room in the toe box. My feet are 27 cm so according to the 361 sizing chart I should wear size 9s.

Can any owners suggest what size I should order?