She's probably lonely and therefore showing her frustration to you. I understand why you are keeping her in the bedroom, but the thing about that is then she's bored, lonely, and feels abandoned. Furthermore, your cats will never get used to each other if they're never allowed to get to know each other. My suggestion would be to only keep the kitten confined when no one is home to supervise her with the other kitty in the house. Otherwise, let them interact.