Is there -9 floor level in tibia?

Question

I have found the stairs on -8 floor, but i think they're unaccessable, but is it leading to somewhere?

Maybe some of you guys had some experience with or info about -9.

Is it even possible?

Answer 1

The only accessible floors are from +7 to -8 . Any staircases, holes, ladders located on a terminal floor leading to another floor in the same direction are just for decoration and atmosphere. 

You can browse all of the currently discovered maps and check your area in question at the supported fansite, TibiaMaps.