At this point, we're just waiting for Oda to give us the formal confirmation. Zoro has every quality to possess CoC His ambition is high, and regarded highly by those who learn of it.
The characteristics of CoC wielder is the disposition to stand above others. Zoro has not bowed to anyone unless it was for the sake of Luffy. Strong pride in himself.
Zoro has managed to tame Enma, a blade that no one but Oden has managed to tame. And what distinction does Oden possess? He is the only confirmed Wano swordsman to possess CoC.
And Zoro was able to tame that same blade with easy.
It can't just be a matter of strong will, otherwise, one of the scabbards like Kawamatsu, Asura would've been able to wield Enma. Remember, Kawamatsu was the same guy who held out for 13 years in Udon, eating nothing but poisoned food, and even he was amazed by Zoro's control over Enma.
Smaller supporting points are various second strongest of pirate crews possessing CoC, though I don't look to hard on that. While you can claim Rayleigh as Zoro's parallel, his possession of CoC was likely just a way for Luffy to learn of it first hand as his master, and Katakuri was build as Luffy's mirror opposite. However, one cannot deny Zoro's established qualities, position in the series as Luffy's right hand, his strong ambition, and will.