You are using the same 'brightness' for both PWM signals.
Try brightness, brightness1
One goes 0 to 255, the other goes 255 to 0, then they change directions.
You could also try brightness and (255 - brightness):
0, 5, 10, 15, 20 ... 240, 245, 250, 255
255, 250, 245, 240, 235.. 15, 10, 5, 0
You've also got some pin9 comments in, left over from something else?