It shouldn't be available during character creation. However, there may be mods that modify who may pick which class/kit, and perhaps such a mod can also affect mod-added kits. That's a possible interaction. Without such tweaks, the kit isn't available, I just checked it.
Lava Del'Vortel, also known as Weasel. Enjoy my mods. They were made by a fan for other BG/IWD fans. Want to buy me a coffee? Read this post first.