Anyways, that looks like a roo to me. What catches my eye is the color and shape of the neck feathers. I believe the long narrow hackle feathers on the neck will continue to progressively turn more and more white while the lower body will most likely turn darker with time. The comb and wattles may have just not had enough time to get darker red yet. And just look at those tail feathers!
I have a roo very similar to it that is about the same size and age or maybe a week or two older at the most and he is crowing to beat the band (started a couple of weeks ago) and mounting an older bantam cochin hen all of the time now. However, some roos develop earlier than others, and I think that mine is developing a little early.
Perhaps you may have noticed in the meat birds and butchering sections that people here have noticed that some roos have small testicles and some have seemingly gargantuan cajones. I think that makes a difference in their development. Birds with more testosterone will start crowing and other roo behavior earlier than others.
One thing that may help you now, depending on how many roos that you have, is to watch their behavior. It seems to me that the young roos recognize other roos earlier than we often can (unless they are sex links). At 10 weeks, you may often see certain chicks (young roos) engaged in stare down contests, often standing up to each other eye to eye with their neck feathers fluffed out. The hens will often ruffle up all of their feathers, but the roos usually only ruffle up their neck feathers when facing off to each other. That is rooster behavior that you should be able to recognize now.
P.S. - If it starts laying eggs in about four months, don't pay any attention to me anymore, okay? LOL... I would be surprised though...