Doesn't sound to me like being a prison officer would suit you. Prison officers are overworked, underpaid and (in their own estimation, and I'm not surprised) undervalued. Anything 'meaningful', ie teaching, counselling etc. in prisons is mostly done by outside workers.
However, with your background and your hobbies, community work sounds right up your street. All those creative and literary skills/interests you have, you could maybe pass on to others - learning disabled, mentally ill, homeless etc etc. Plus you say you'd like to help others, which is exactly what you'd be doing.