I’ve never done this; I could be completely wrong but since no one has answered I’ll offer what I think are two feasible strategies.
You can evaluate them and see what path works best for you.
I believe you’ll have to remove the worm gear in all cases to avoid damaging it and to just get good access to the bushing. I don’t have one of these trucks out at the moment to judge and I can’t tell from your picture.
The first strategy would be to use a press and a custom tool and anvil. The anvil would have a well to receive the bushing as the tool presses it out of the plate. The tool would have a centering pin and would extend out to cover the bushing but no more. In addition to the well, the anvil would support the aluminum frame.
If you don’t have a press and a lathe to make the tooling then maybe the next best thing is to get a socket a little bigger than the bushing and use a tapered drift pin / punch to push the bushing out from the top. Similar concept as the press and custom tooling but requires more coordination and you’ll have to tap the tapered pin with something hefty.
You also probably want to apply a little lubrication around the bushing.
I could be completely wrong and there may be a magical way to do this that is so simple we’re overlooking it.