You are correct, Mauricio. “Wanna” and “kinda” should never be used in writing (unless maybe you’re a teenager and you’re texting your best friends). “Wanna” and “kinda” are not words — they are simply attempts to represent the usual pronunciation of “want to” / “want a” and “kind of” in normal speech. These reductions are inevitable results of English phonological “rules” that native speakers apply unconsciously (if you draw their attention to it, they may get upset — hence the need to avoid writing “wanna” and “kinda”). Please, do yourself a favor and use standard spelling.