I want to use 4x MicroServo with 9V battery
9V batteries can't supply high currents.  If you connected 4 servos in parallel to one battery, the voltage probably dropped far enough to be safe for the control circuits in the servos.

You need around 6V to operate your servos, and you need more current (and capacity.)

The solution is to use 4 batteries in series that provide about 1.5V.  Servos aren't terribly picky, so it's not a problem if the voltage varies a bit.

You could use AA batteries, or C, or D.  All will give you enough current and capacity to be useful.

You can use alkaline batteries, or rechargeable NiMH.  Or a lithium ion battery pack with appropriate charger.



Your voltage divider didn't work because it also reduces the current available to the servos.  Your divider lowered the voltage to the servo, but because of the resistance of the divider there wasn't enough current to the servos for them to operate.