It didn't bother Sora. In actuality, Sora didn't care if they acted like they were dating, as long as both of them were clear that they weren't. Sora was afraid it bothered Riku, or gave Riku the wrong idea. He was also, in the back of his mind, terrified that if his best friend realized they acted like they were dating, he'd not want to be friends anymore. It was pretty far back there, but it was still there.
"See you at lunch," was all Sora really said after stopping briefly at Riku's classroom and continuing on to his own.