With such a high population of suburban possums around - removing from your home is just opening the door for another to move in.
Instead, try confining them to a particular part of the garden by putting up a nest box and putting out some food, such as fruit or vegetables.
For a Possum-Free area around ornamental plants and fruit trees use a deterrent, such as: Quasi Chips, Blood & Bone or Multicrop’s SCAT (bird & animal repellent)
SCAT– Mix with hot water, allow to cool, place in trigger-spray container and spray the plants foliage. SCAT has an odour and bitter taste possums don’t like, and is safe and effective. Keeps working for 10-12 weeks.