At 8 I would say he is past the 50 stage, unless you want to buy another one next year. 2 wheels I would suggest crf 70, yamaha 80, or klx 110. Worried about the clutch? Don't teach him to shift until he's comfortable, just keep him in 2nd gear. 4 wheels I would say honda 90, or polaris 90. Not sure about the Honda, but I had a Polaris, its auto with a throttle limiting screw. Thing held up well, pulled me around just fine too, Only caution Deep water fried my Stator oem $160.