I recently figured out you can use custom virtual console injects on wii u and play deadly silence this way. It's incredibly stable and i was wondering if anybody tried it for speedruns? Also if end up running it myself would this be accepted on the leaderboard?

As far as I know, no one has tried that. If you wanna make a recording of a run with it and post it here, we'll give it a look and discuss adding it. This doesn't seem all that different than using an R4 card on an actual DS, so unless something screwy goes on with this, I don't see any problems with accepting it.