I'm 9.5 and I like a 10 in prestos. 9 feels too snug width wise.
I wear a 9 in sock dart for reference
If you have a narrow foot then the smaller size may suit you better. Depends on how you like your fit.
I just got some finger trap TR's and I'm loving them.
Great cushioning and support.
For anyone interested they run really big. I recommend half size down.