What should I do with a new kingdom?

I'm currently the Sunni Caliph and have the Sultanate of Mali title. In my game there are only two Sunni Kingdoms (my own and the Almavorids) and a pretty powerful duke that controls the other half of Mali. Anyways, I called a Jihad and won the Sultanate of Andalusia. I am trying to figure out what I should do with the new land.

Should I keep the Sultanate and split the land up amongst new vassals?

Should I give the kingdom to my heir?

Or should I give the kingdom to a random Sunni in order to create a third Sunni Kingdom?

If anyone can help me out I'd really appreciate since this is my first time conquering a whole new kingdom! Thanks!