With the 2018 Easton S650 -5 USA Baseball Bat: YBB18S6505 being a one piece alloy bat, the player will feel vibration, even sting, when the ball is hit off the end or down toward the handle of the bat. However, if you hit the ball squarely, little vibration will be felt.
The 2018 Easton S650 -5 USA Baseball Bat: YBB18S6505 has a USA Baseball Stamp. However, you can swing a USA Baseball Bat in a USSSA sanction league. Just keep in mind that you might be at a slight disadvantage using a lower performing USA bat.
Based on your player's height and weight, I would make a general recommendation of getting this 2018 Easton S650 -5 USA Baseball Bat (YBB18S6505) in the 31"/26 oz size as long as he can handle that weight. If your player is being required to swing a USA bat, I think this would be a solid -5 bat for consideration.