Saying "wanna" is extremely informal and slang way to say "want to". I would say, "Who do you want help from".

'Wanna' is a phoneticisation. It can be short for 'want to', or 'want a'. You can pronounce it like that, and we often do, as Paul said. But you should not write it, as it can be confusing, and looks a little ignorant. Your word order 'out you' is the wrong way around. It should be 'you out'. Are you sure your teacher wrote it that way? If they did, perhaps you should get a better teacher!

Personally speaking, I would say "Who do you want to help you out?" Or "Who do you want to help you?"

Hi Ito, Your use of "wanna" displays informality instead of impoliteness. For example, a high school student will most likely use it with his peers to suggest a trip to the mall (e.g. You wanna hangout?) but a lawyer would almost certainty not use it for a closing argument (e.g. The truth, if you wanna know...). If he does, he will come across as being rude and disrespectful to the solemn nature of a court, but more importantly, he is frowned upon because he shows disregard for the place, audience, hierarchy, formality and purpose of his speech — the register. "Who do you wanna help you out?" It sounds clumsy to use "wanna" here because the word "you" is used twice: "Who do you wanna" = "Who do you want" refers to someone you have in mind. At the same time, "wanna help you out" = "to help you out" refers to the intention to assist you. Phonetically, it can already sound confusing if you say, "Who do you want to help you out?" quickly, more so if a slang is used. It would be better to simply ask, "Who do you want help from?" I hope this helps.

English is not exactly my native langauge but I feel like the only correct option is "who do you want to help you out?"