I don't think he'll look different/be left out if he doesn't have a phone (many kids in my 6th grader's class don't have phones; my son is one of them). That said, if you're going to get him a device anyway, might as well go for the phone. It really does make life easier. There were a few girls in DD's class and girl scout troop this year who didn't have phones (she just finished 8th grade), and it made organizing social events and/or troop things much more difficult. Oh the other hand, DS did make it through 6th grade without one. If he forgot to tell me about a club meeting, he'd just go to the office and call me to tell me when he needed to be picked up.
For some reason, we decided that 7th grade was when our kids get a phone. That worked well with our first kid, but honestly our middle kid could have waited a year. That first year, I consistently had to remind her to bring it with her to practices, social events, etc. She didn't actually start using her phone much at all until this semester.
DC1 -- 2005 DD -- 2009 DS -- 2011