As a level 9 artisan, you are about due to go and declare the profession you would like to continue to advance in. Your XP will be capped at lvl 9 until you make this choice.
In Qeynos, the guy you would need to talk to is in the building that is under construction near the water in Qeynos Harbor. I don't know who you would talk to in Freeport.
Your choices at lvl 9 are Scholar, Craftsman or Outfitter. You will remain one of these three for the next 10 levels and at lvl 19 you will speak to another NPC and choose your final speciality.
Scholars can become Alchemists, Sages or Jewelers.
Craftsmen can become Cooks, Woodworkers or Carpenters
and Outfitters can become Weaponsmiths, Armorers or Tailors.
After you choose a speciality and reach lvl 10, you will receive tier 2 buffs for all three of the options in the area you have chosen.
When you reach lvl 20 and have made your final choice, you will receive a single set of tier 3 buffs for your chosen skill.
Although you are required to specialize in one profession, you can also learn to make items required for your craft but outside of that discipline.
There are 4 cross over arts called Weaving, Timbercraft, Apothecary and Geomancy. Books for these skills are available in the T/S instance where you do your work and will allow you to make sub-combines without having to buy them from other players.
So for example, if you are a weaponsmith, by using timbercraft, you could still make the wooden shaft for a pike and not have to buy it from a woodworker. And as an armorer, you could use Apothecary to make the tempers needed to refine metals into heavy armor without buying them from an alchemist.
Remember that you can also craft boxes for storing things in your bank inventory slots. Boxes tend to have more slots than bags of the same level so they are a better bet for bank and room storage. Only Carpenters can make boxes from tier 3 and upward but any craftsman can make tier 2 maple strongboxes, (12 slot), and anyone can make tier 1 elm boxes, (8 slot).