Why am i not able to wear it someone told me to use the /hat command and it says i dont have access to that command
Try to wear it like you would a helmet by bringing up your inventory and placing it there.
You have to have donated money to have access to the hat command where you are able to place blocks on your head.
Once you make at least a $5 donation you can use the command /hat when the jack o lantern is in your hand.
that jack 0 lantern will wear YOU