Haha, I'd let the fangirl in you go free for now.
It could be fake, but this strikes me as something that's probably real.
I really strongly think that this is Bono's voice. It sounds way too close to be questionable for me. Furthermore, to me at least, it sounds like how Bono's voice has been quite recently, not in 2004 or 2006 or 2008. Also, I think this is an IEM recording. We've never had IEM beach clips before, which would indicate at least that this isn't some lost part of one of the beach clip tranches we've had in the past. If it isn't IEM, if it's just recorded from outside... there's no beach sound! And for this to just be an elaborate hoax and sound as it does... it would take
incredible editing skills, and probably lots of time and money if it's even possible at all. It sounds too much like exactly how I'd expect an early U2 demo to sound to be a hoax, in my opinion. Frankly, I don't think anyone would care enough to invest enormous resources into faking a U2 demo like this.