Song meaning of Starman by David Bowie

Alright, so we've got "Starman" by David Bowie. The song starts with "Hey, now now, goodbye love." I mean, what kind of mixed signals are we getting here? Is it hello or goodbye? Bowie, make up your mind! Anyway, he goes on to describe how he was listening to the radio and heard some cat layin' down some rock 'n' roll, which he thought had "lotta soul." But then the music fades and he hears a "hazy cosmic jive" that he attributes to a starman waiting in the sky. Apparently, this starman wants to meet us but thinks he'll blow our minds. Look, buddy, if you're gonna travel all this distance to meet us, don't be a tease. But at least he's told us not to blow it. I'm guessing he has way more faith in us than we deserve. The starman even gives Bowie some advice to "let the children lose it" and "let all the children boogie." Sounds like a plan to me. But then, just when we think everything's gonna be okay, he warns Bowie not to tell his poppa or they'll get locked up in fright. Wait, what? Is this some Men in Black-type stuff? Bowie, who is this starman and why are you keeping secrets from us? Also, is it just me or does the outro sound like a bunch of la's? Like, if this starman wants to communicate with us, I think he needs to work on his message delivery. All in all, I'm not sure what to make of this song, but I'm definitely intrigued.