Laufey was standing in front of a packed crowd of some 12,000 adoring fans at Oakland Arena. “Welcome to my jazz club,” said the Icelandic pop star, whose recently released third album — “A Matter of Time” — does indeed currently sit atop Billboard’s Jazz Albums chart. However we want to categorize Laufey (pronounced LAY-vay), the fact is that she’s got a sound that has deeply — and quite unexpectedly — connected with younger listeners. Of course, that would be a very good trick, since Laufey is still just 26-years old — and these are original compositions. It would be so embarrassing if you weren’t.”Suki Waterhouse opened the concert with her own roughly half-hour set of fun pop songs.