Hi, we're cruising the east coast
of OZ and have had a number of tenders over 4 years.
We started with a fibreglass tender
(10') which came with the boat. It was heavy and unstable. We then bought a cheapish ebay inflatable
with an inflatable keel
which was fantastic and would plane with 2 adults with a 3hp. The tubes also make great fenders when coming alongside! If you're planning on staying around Bris these may work for you. The limitations are heat-you need to buy an inflatable that has been made with a glue that will withstand Oz heat. Most of the cheap
ebay inflatables seem to be made in China
and will come unstuck after a year or 2. Also you need to carry them over any hard surface.
We then went to a tinnie(3.8) whilst in Moreton Bay with a 15hp Yamaha. It planed easily, was incredibly stable with a false floor and was a great workhorse. Downside was weight (a little too heavy on the davitts). If we could have found a smaller tinnie that was rated for a 15hp we would have bought it, they are especially great for NQ (crocs and coral).
We then tried another fibreglass tender (cathedral hull) but it was unstable with a 15hp on the back.
So our tender now is a southern pacific 3.1 rib
with alloy floor. It's rated to 15hp and it flies and is very stable. It hasn't got hypalon tubes but with pontoon covers it will probably last as long my research
As far as outboards, I know the parsun is becomming popular here ( I priced them recently in Maryborough and the 15 appeared to be more expensive than the yamaha, go figure) I'm really happy with our yam 15, but if I'd known the 9 was pretty much the same motor
I would have gone for it.
Good luck with what you settle for