The main problem is calculating haw the ball is going to bounce.
The way i would do it was to make a circle of points
around your ball,via cos/sin
and check which of of these points are touching a wall. U can use this to work out the angle of the wall, because a tangent will always be at right angles to a line drawn between the centre of the ball
and the point of collision.
Ps a tangent is a line that just clips the side of a circle, and only just touches it.
PSS why isometric? top down or3d would be soooooo much easier (blieve me)
Life is a terminal disease.
You never survive it.