Since R is out of bounds when the ball touches him, the kicker has caused the ball to be out of bounds. See case book 6.1.8 Situation C (b) (on page 43). If the covering official rules R touches the ball while OOB, K has fouled.
If R catches the kick while airborne and then steps OOB, or if the covering official rules R caught the ball then stepped OOB, K has not fouled.
Rule 9-6-2b states "no player shall intentionally go out of bounds during the down and intentionally touch the ball." So unless the covering official ruled R12's action intentional (and it appears it was not), R12 would not be guilty of illegal participation.
Rule 9-6-1 applies to A or K, not B or R.