How do I size on the Yuketen boat shoes like these?

Sperry 10: fit well, but just slightly loose on the length, not unwearble or anything
McNairy Saddles 9.5: Fit is same as above
Clarks DB 9D: Same as above
Common Projects 9: Perfect
LANVIN 9: Perfect
Alden Indy 405: Don't own them yet, but remember trying a 9D and it fit pretty good.
Red Wing Classic Moc Toe boot: I can fit 8.5E or 9E.
I am guessing in Yuketen boots I would likely be a 9D, but do the boat shoes run just as big? Should I size up to a 9.5?