Boost converter massive voltage
Boost regulator IC use feedback to control the voltage. When the voltage gets too high the IC backs off the duty cycle and when the voltage gets too low the duty cycle is increased. Some boost regulator ICs will even switch operating modes depending on load.

The boost converter you put together is open loop, meaning there is no feedback. Without feedback nothing controls the duty cycle to regulate the voltage. The open loop setup is very load dependent. The larger the load the lower the voltage. 

What you can do is use a potentiometer to make the duty cycle of the 555 adjustable and then tune the converter to the load. The only problem would be is that the load would have to be constant.