Are the crafter soul crystals worth it?

[Nicodemus_Mercy]

Alrighty. Is there a particular level I need to get the other jobs up to or do I need to max them all out?

All crafts to 50 covers all the cross-class skills. Beyond that you can simply focus on the one you want to pursue, but most crafted items require materials from other crafts. Without the rest of the crafts leveled to process any materials you may need, you'll have to buy them from the MB.