MC34063 9v to 5v doesn't give expected voltage
I assume by 10mH (10,000uH) you actually mean 10uH. 

10uH is way too low an inductance for the MC34063. You should be getting numbers more like 100-200uH. 

Try an 'official' XLS spreadsheet from Onsemi. 

I get more like a 170uH inductance, and maximum output current more than 500mA if you can stand 0.56W dissipation from the chip alone. Efficiency about 52%. 

You need an inductor that will not saturate with 0.55A current.