I had the same issue before where I would hear the laptop turn on, battery is working, but no display. I took it too the apple store and the Genius Guy said that the display was disconnected, probably from when i was working on my laptop. My suggestion is to take it to the apple store and say that your macbook wont turn on.
[Was it a lot of water and where exactly on the laptop it spilled? I spilled soy sauce near the trackpad and it got on the battery (genius guy at Apple Store said it got on the logic board) but I didn't see any. I would try to checking the logic board carefully if corrosion is occurring (which could be brushed with a soft paint brush and 90% or above isopropyl alcohol) and if your laptop was soaked you might have to replace the battery. Here is the guide for teardown for your MacBookMacBook Pro 13" Unibody Mid 2009 Teardown