Hi there, welcome to BYC!
I 100% agree with the first poster who said SLW CROSS cockerel.. NO questions asked if stated age of 9 weeks is correct.. and I don't care about individual differences.. even twins with the same genetics display differences.. full sibling inherit a MIX of the parents genes.. This BOY has a straight comb which would be ROSE if he was full SLW. His sisters are displaying muffs and more like pea combs.. it's like comparing apples to oranges and not really relevant since they aren't PURE and can get any combination of traits from their parents. Also the wide white barring on the shoulders is very typical of male pattern.. you can hold out hope if you want.. or you can accept it and move forward.. too much experience here to deny the one in questions gender and try and hold out with you. Maybe
his comb appears narrower than your other cockerels because it has more straight inheritance than the pea or comb the other boys MIGHT have?? The size and color of both the wattles and comb development are EXTREMELY telling.
Saddle feathers start coming in around 12 weeks on most breeds..
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Best wishes re-homing or sending to freezer camp

(or whatever plan you made for boys before deciding to hatch)!
Adding your general location to your profile can help folks make their best suggestions possible at glance for things like re-homing, etc.
They are lovely birds btw!