I agree the kitten is playing, the poor goose just doesn't see it that way, when I was a kid we had a cat that would squeeze between the wall and refrigerator and wait for someone to walk by and jump out on them, scared my grandmother many times. lol I think the goose and cat will work things...
I don't have any cats or kittens but I can relate to how dogs and geese and ducks relate. My dogs are scared of my geese and will be mean to them so I don't let them interact unless I am with them. Eventually your goose will stand up to the cat but it's still young so it will take a while...