what should i do?

Today (9 days after mixing the substrate) I found a drop of water falling from the side of the tub to the substrate surface. I quickly disinfected the growing area and used a paper to absorb the drop. Will this slow down the colonization process? When can I use polyfill or micropore tape to proceed to the fruiting process? Can any expert tell me if the surface in the picture can be Fruiting Condition?

Water pools are not good, but a few drops on the mycelium aren’t a problem at all!

Here are some examples to ease your mind and show you mushroom fruiting with water drops:

You used paper to absorb a water drop — that wasn’t necessary, but it’s fine. However, any kind of 'disinfection' isn’t needed here. I’m not sure what you used, but if it was alcohol or hydrogen peroxide, it could also irritate or damage the mycelium. So, it could slows the mycelium down in that area.

As for fruiting conditions, you could wait another 1–2 days, but I’d providing them right away. The mycelium looks good, and there are already some tiny knots forming ;)