Analyzing the crystal frequency (Bus Clock Frequency) of a HCS12 Microcontroller using an Oscilloscope
This MCU has the typical Pierce oscillator configuration.  

Based on your schematic, if you attach a scope probe (use 10:1) onto pin 14, you should see an 8MHz periodic waveform. It won't be a square wave but it should be fairly large. 



You might also see something similar on pin 12, but without an FET probe it may not be right because the scope probe will disturb the load capacitance on the crystal.