or can you be dedicated to the virtue without spending xp, you just cant dedicate others to it?
If your character starts with the Dedicate skill, you can pick an Imperial Virtue to be dedicated to at the start of the game.
If not, you have to become Dedicated in play, which requires a priest of the appropriate Virtue to spend 1 Liao (for a basic Dedication, anyway).
You can only Dedicate others if you have the skill and spend the necessary Liao. Again, no XP spend is required, apart from that to take the Dedicate skill.