You do not need special hardware but you do need a device that has XGATE on it. The 9S12DG128 does not have XGATE.
XGATE is fully programmable in C so you don't have to learn a new language. The best place to start is with a project template from CodeWarrior or Cosmic. You can learn about how to configure the interrupts to go to XGATE and how to have XGATE handle them by reading any of the XGATE LIbrary app notes or AN3144 for a simple project example. You can also search this forum for more user examples.
