Wow, well I was excited to see the 9-00 boon, and have made a character accordingly!
It's pretty clear that under RAW, any spellslinger must still pay full price for ammunition, regardless of ranks in craft alchemyy. To wit
the Roleplaying guild Guide for season 9 wrote:
Ranks assigned to Craft skills are used only to perform Day Job checks, not to craft mundane items, with the following exceptions.
• Alchemists can use Craft (alchemy).
• Gunslingers can use Craft (gunsmithing).
• Investigators can use Craft (alchemy).
I do wonder if there are any plans to FAQ this, so that those with a spellslinger boon and craft alchemy can make their own ammunition ingame. Meanwhile I'll keep dropping points into craft alchemy, and toting around my molds and tools for melting lead, and for mixing saltpeter sulfur and charcoal, while paying Guaril Karela's exhorbitant rate for bullets powder and cartridges.
Many thanks, Doctor Boem