i have a cyclone 2450 360.15 that has gone bad - can i replace this with a Motorola 2450 AP P9?

What is a "360.15"? I assume you want a replacement for a 2450 AP that has an integrated omni? No... not directly... not without having a 3rd party connectorize the 2450 AP or doing it yourself and then using an omni antenna on the new port. Keep in mind this will certainly void your warranty and may be in violation of certain governmental restrictions... but many people do this.