I'm 95 kgs too .i use 8.5 ...have a few mates lighter @75- 80 kg they have 8.0 s ...might be too small .we all wave sup .and flat water with the same paddles .
The 91sq" should be good for you. its very hard to say on the interweb though. How tall are you? the various shaft options can have a big impact too, me personally I use the Elite Flyweight shaft but then I cut my paddles down to about 61" - 63" total so the Flyweight works well. The round tapered shaft is the stiffest with the oval tapered next.