Seeing as your cat is still quite young, there may be time yet to calm her down. Firstly, I don't think your cat is actually "spiteful" but perhaps just frightened. Try this: wait until she is in a quiet room with no distractions or loud noises, then go in yourself and close the door. Hopefully this shouldn't trigger the hissing. Sit quietly without looking at her - perhaps read a book or something. From then on, just take small steps to see how much she will trust you. A good start, I've found, is to place some food or treats on the floor near you, and to ignore the cat when she eats them. Add more treats, so the cat can see you doing it, but only move your arm very slowly (as this might be what she finds so terrifying) and still ignore her. If you find yourself getting scratched at this stage, pulling away tends to make things worse. Our cat used to enjoy clawing hands and feet, but would get bored and let go if I just let him scratch as much as he wanted, with me staying still. If this doesn't work you could push towards your cat when she lashes out at you (they seem not to expect this) and hopefully she will not retaliate.
The most important thing is to take things slowly and to never attempt to pet your cat until you're sure she will accept it. A hand swooping down towards her might seem alarming at this stage, so show her your hand first, at ground level. Most cats would want to inspect and sniff the hand, and this is usually a good time to introduce food. If all goes well, after a few weeks, she shouldn't see you as a threat anymore, and might even accept food from your hand and let you gently stroke her. All cats are different, though, so some will always be a bit scratchy. I hope things work out for you, Debbie.