There are two main reasons for this:
1. Nine-tailed Pokemon are a concept from later generations. Crystal is the second generation of Pokemon games, and the concept of nine-tailed Pokemon (specifically, the legendary Pokemon, Ninetales from the first generation) does not exist yet.
2. Ninetales is already a fully evolved Pokemon. In Crystal, Ninetales is the evolved form of Vulpix, and there is no further evolution path.
If you are looking for a powerful fire-type Pokemon in Crystal, your best bet would be to train a Vulpix to its final form, Ninetales. You can find Vulpix in the following locations:
* Route 34: This route is a popular spot for encountering Vulpix.
* Route 46: Vulpix has a higher chance of appearing in this route.
* Ilex Forest: You can also find Vulpix in this forest.
Remember, Ninetales is a strong and versatile Pokemon with good Special Attack and Special Defense stats, making it a valuable asset in your team.