My generation did not ever use 'wait on' unless it was specific to a server waiting on patrons in a restaurant or at a dinner party. A maid or butler would wait on you as well.
Now, most of us do not have maids or butlers and the only person 'waiting on' us is a wait person/ server.
I am waiting for the bus. I am waiting for spring.
In writing, waiting for is the accepted usage outside of the server/maid example. In speech, it is slang/colloquial (but not yet 'correct'*) for people to say, "I'm waiting on the bus." In writing that would mean you are literally waiting on the bus for an event to happen. "We waited on the bus, for the driver to arrive." This means we were inside, on the bus while we waited.
I said not correct* because if you are in a formal setting and trying to impress a potential employer or anyone important to you that you have some education, you should try not to use colloquialisms -- unless you fully understand them. It doesn't matter what those might be. Slang or colloquial speech is still unacceptable in some situations. Until you know those situations, I'd suggest you speak more formally. Everyone will understand you. ON EDIT: Here is a link -- but you can google this easily.
I don't know if this is the same where you are from, but I automatically do not use swear words in many situations. I don't need to be told or have it explained. I just know not to swear at my teacher, the boss, a child, and so on. Other colloquialisms are similar. "Wassup?" might be perfectly acceptable to your group of friends, but totally unacceptable to your potential boss.
Justin Bieber is writing poetry/lyrics. There's a lot of leeway and license given to artists in their choice of phrasing and word usage.