Basically you want to set the transform
of your bullet to the transform
of your player.
So, after you create the bullet with this:
var bullet = BULLET.instance()
Set its transform to that of the player
bullet.transform = transform
Note, this assumes the running code is on the player object, but I think it is... Also, you could attach some bullet spawn point to the player object (like right at the end of a weapon) and start your bullet there instead. It'd be basically the same thing, except you'd be setting the bullet's transform to the transform of that "spawn" node instead.