Depends on what you want?
Patty is probably one of the first ARF's to come out capable of handling a small gasser and there have not been many changes to the model since it's introduction. It's fully sheeted and tough as nails when compared to some other lighter models, but even at her weight which usually comes in around 16 1/2 to 17 lbs. it still fly's better than it's wing loading might suggest. An excellent gas trainer if you ask me since that's what I used...
While I have no direct experience with the H9 Extra, certain reports suggest there is a problem with the rudder not holding up to gassers and while I have my own opinions of graphite gear, that has also been problematic with the H9 and IIRC, it's offered with either an aluminum gear now, or a replacement in aluminum is availble, can't remember which.
Of your engines mentioned, I think most folks would recommend something in the 50cc class for Patty while it's a bit big for the H9. I have seen one of those H9's with a ZDZ-40 RE and it was a spectacular performer even here at 4500' ASL.
While I also have a bigger model, I wanted something a bit smaller that fits in my Jeep like Patty did, to go play with as getting the Edge out requires hooking up the trailer. I looked at the various 50cc offerings and there's not much question that the AirWild 29% Extra is probably the lightest, but it is on the spendy side as well. Then there are others which guys on the GS Aerobatic & 3D forum like, but I decided on trying a Bunny as they've got an excellent reputation and since the release of the newer versions are all quite a bit lighter than they used to be. We'll see how heavy it winds up being, but for the money it's a pretty tough act to follow if you ask me; great workmanship, lightweight and really good CS with WildHare.
Do a bit of searching on the Aerobatic forum, you'll get lots of suggestions! [8D]