Yes, llamas — and, by the way, alpacas as well — can spit. The animals spit at each other due to competition for food or to establish and maintain the hierarchy within the herd. Llamas tend to spit slightly more often than alpacas.
Our animals only spit at each other, not at people! Animals that are raised and kept in a species-appropriate way, have enough space, and are treated with respect do not spit at humans.
The finest wool in the world comes from vicuñas. Their fiber extremely fine and rare, making it one of the most valuable and expensive natural fiber in the world.