
At the edge, I approach Wario a few different ways when it comes to grabs.
These are all assuming a reasonable grab release percentage, like 80% or something.
I think the most reliable thing to do him is to just keep chewing and then release into a fresh up aerial at 130%. I have yet to experience Wario get out of this on any stage if the up air is fresh.
If for some reason you need a really quick bursty kind of KO, you can nail a Wario using
reasonable DI at maybe 110% or so with forward smash. You might need this on stage changes or if some sort of something is going to prevent you from getting another grab on your release. I have seen absolutely perfect DI on a forward smash out of release and the Wario survived when the hit came in at around 125%.
If you just need damage out of a release and either you want to save up your forward smash (LOL) or you want to get something out quickly and forward smash won't come out in time, you can just upsmash, but I've upsmashed Wario at 170% and he's managed to live, but it was probably 1 or 2 notches into the move queue, so the fresh KO percentage would be a little deflated from that.