You can use the other half of your CD4013 for debouncing. Note that the Q output will be low in the steady state, because when it goes high it resets Q to "0" after the RC delay. Now, when the button is pushed, it clocks a "1" into Q (because the D input is a "1"). Additional clock pulses, due to switch bounce, will have no effect as long as the bouncing ceases before the Reset input reaches the logic threshold.
When Q goes to a "1", the capacitor on the Reset input starts to charge at a rate determined by R and C. the voltage on the cap is
V=9*(1-e^(t/(R*C))) where e=2.71828
Solving for t,
t=R*C*(-ln(V/9)) where ln is the natural log function
Assuming the logic threshold is 4.5V, then t=0.693*R*C
In this case, the width of the pulse on pin 13 will thus be about 15 milliseconds. Most switches stop bouncing in less time than this.