The singer-songwriter, 25, was one of the only “Idol” finalists to ever perform songs he’d written himself, which may be part of the reason he only came in second, and the judges were fulsome in their praise. “I just feel like I’m in the presence of greatness,” said Luke Bryan. Katy Perry asked if she could roadie for Aranda on his almost-instantly-sold-out first headlining tour, which hits the Vic Theatre Wednesday. Stevie Nicks said he made her cry (she wasn’t actually a judge, but still).