Sorry spell check corrected my spelling
If you like the name Edison and don't want to possibly open your kid to teasing, there is Addison for the same sound.
If people will think Christian when they see Christion, they will just think it is spelled wrong. And of course, the hero of all those sex/bondage novels is named Christian, so as long as the book is well-known, even someone named Christion will get a little kidding. Edison is better, though of course some teasing possibility there also, "light bulb" and stuff.