"I confess that I don't remember where I met Xion initially, but we were colleagues for a short time. Riku I encountered in the course of my work, but we were in conflict, largely due to the results of Xehanort's machinations." He doesn't have to mention his attempted murder. It likely wouldn't go over well, considering the situation, and besides, if Riku hasn't shared it around, he's under no obligation to destroy his reputation with it.