You were level 10, because that's the first level Lightning is available to put skill points into. I also should note that you can't reach level 10 from just the catacombs, you also need to clear a bunch of the forest around Aleroth as well.
Okay, level 10 or maybe 11, you're right, level 9 can't be ...

No, I can't reach level 10 doing only Aleroth and the Catacombs ...

But yeah,
why NOT going outside Aleroth and killing Orcs???

It's an RPG and a seemless world to GO !! Last I was just level 2 and going killing some Orcs

... nearby death, but that's my problem