Just like you would cook any steak, but make sure it is done rare.
Wagyu beef is especially juicy because it has so much fat marbled through it. Kangaroo steak gets really dry and chewy if it is cooked through because it is so lean and has almost no fat.
I was once buying kangaroo from a supermarket and a guy working there asked me if it was my first time having kangaroo(which it wasn't). He told me he used to be a chef in Darwin, and they'd get all these American tourists come through, and they would all order the kangaroo because it was the touristy thing to do.
He said that despite telling them how dry kangaroo is and trying to get them to have it rare, they would insist on having it well-done in the typical American style...then they would all complain about how chewy and terrible it tasted after.
I don't like kangaroo as much as normal steak, but I still enjoy it. If you can't handle rare meat though, it may not be for you.