First off, we need to address the fact that your CB will often "press" the X receiver, even if you don't manually do so pre-snap. Therefore, you are vulnerable to a 9 or streak route.
What works for me
most of the time is to make sure I select coverage assignments pre-snap and play my corners over the top. You will see a brief press animation and then the corner will employ a "bail" technique.
I strongly recommend that you employ cover 1 hole-align and press corners-play bail coverage, rather than continuing to play man under. I will also sometimes play outside leverage which will give a brief press animation as your CB will turn and run with the receiver more quickly. I highly recommend using that technique when playing cover 2 zone defenses.
I play on All Pro with
user defeated sliders only evenly disbursed at a total of -50 points with cpu points on default and speed disparity scale set @ 25. Hope this helps. Good Luck.