analogWrite mosfet problem
You have a timer conflict.

Pin 9 is OC1A which is the Output Compare Channel A pin of Timer 1. However the Servo.h library also uses timer 1.

So you can't use servos and still use pins 9 (OC1A) and 10 (OC1B) as PWM.

However, you can still use pins 3, 5, 6 and 11 as PWM since they are on other timers.