Q: 2005 Volvo XC90 Alarm System draining battery - removed fuse - still draining

It seems as though you are describing multiple electrical problems. However, the issue with the battery draining has to be resolved first. The battery should be load tested to rule out the the possibility of an internal short or otherwise poor condition as a factor. Charging system output should be verified, too. If the battery passes a load test, and yet the battery discharges in a brief interval with all circuits commanded off, then it is likely that a "parasitic" load, sometimes know as a phantom load, exists. The cost to resolve such an electrical fault is in part made up of diagnostic time and, in part, the cost of materials or components to effect any required repair if the the parasitic power draw is due to a failed electronic module, relay and so forth. If the electrical fault causing current to flow is pinpointed quickly and readily it should not be too costly. Basically, using the factory wiring diagram, a Mechanic would use an ammeter to test vehicle circuits, segment by segment, until the fault is found. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an electrical diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.