Stop wrestling. Wrestler A is out of bounds and wrestler B has at least one supporting point out.
OK, so supporting points are still supporting points regardless of whether they are supporting weight at the time. For out of bounds purposes, the out of bounds line forms a "cylinder".
Similar situation when wrestler A takes down wrestler B and wrestler B is completely out of bounds and wrestler A has his feet on the mat inbounds and his knees are off the mat. Continue wrestling if wrestler A's knees are within the "cylinder" and stop wrestling if the knees are outside the cylinder. Doesn't matter if the knees are touching the mat or not. They are still the supporting parts.
Agree with Akin, this is an of bounds situation (High School) and the match shall be stopped.
In the other scenario, there is no cylinder in high school and toes are not supporting points. What this rule allows is an opportunity or not to establish control. If A takes down B and B is out of bounds and the only thing inbounds is A's toes, there is either control or not at that instance. A does not get the opportunity to gain control, it is either there or not or 2 takedown or nothing. Now if the knees are in bounds, the knees are considered supporting points and A can work to establish control if he hasn't secured it.