At 8 weeks it's a bit too early to tell for sure. Your little bird has some pretty big wattles but WCB females have quite large wattles too so it can't be too much of an indicator at this stage.
If you could post some pics of your bird stood up that would be great so we can see how it's tail is set.
I'm 60/40 that you have a cockerel there I'm afraid. The crest is just starting to hang down to the sides which would indicate male to me. The tail set seems to be developing male too.
I maybe wrong though as polish sure are pesky to sex, I've had them keep guessing until 6 months so all is not list for you.