Will this fit a child with an unusually large, onion shaped head? my child has an unusually large, onion shaped head. not a charlie brown head.

Noooooooo, it won't; It's actually a little too big for me but I still love it!

what does 9forty mean?

I think its due to its style, new era has different styles n names such as 59fifty aka the "Brooklyn style" cap etc9forty was created in the 1940s."Late 1940s: New Era debuts its adjustable size cap." So since the 9forty is an adjustable cap n also has irs curved visor n snug fit vs the 59fifty thats the "fitted cap" made in 1954.

For my 8yo nephew huge fan. Wool or cotton? Will it fit 8yo large headed kid? Quality good? Nice looking? Cannot do "cheap", family does MLB parks.

It is 100% polyester. It should fit youth, it has the Velcro strap in back so it's not fitted, and has the hole for women's ponytails. It looks good and has the genuine merchandise label inside the hat. It's New Era brand 9Forty. I hope that helps!