This problem is so much easier on a digital clock ... but ...
There are 360° in a circle.
Between any two numbers on the clock, there will be 360° ÷ 12 = 30°. (This means that the hour hand moves 30° when going from 4:00 to 5:00.)
I'm going to measure all the degree from 12:00 going in a clockwise direction.
First, let's just consider the hour hand.
At exactly 4:00, the hour hand will be 4 x 30° = 120° from 12:00.
At 4:09, the hour hand will go another 9/60th of the distance from 4:00 to 5:00. (9/60) x 30° = 4.5°.
So the hour hard will be 120° + 4.5° = 124.5° from 12:00.
Now, let's consider the minute hand. After 9 minutes, it will be 9/60th of the way around the dial, so it will be (9/60) x 360° = 54° from 12:00.
The distance between the two hands is: 124.5° - 54° = 70.5°.