Yes, you can only level Dragoon if you bought the Dragoon book.

I will inform you however that Summoner and Scholar still share levels through the arcanist class, so using a Tales of Adventure on Summoner or Scholar, will also level up the other job to 60. You will however still have to do the 10 odd job quests for the class you did not buy the Tales for. This isn't generally bad as the quest lines are generally entertaining and can be done at the locations you will see in the MSQ on your way.

Scholar and Summoner are both having an identity crisis currently though, as both jobs have lost a large number of their DoT abilities. They still work very well in their respective roles, but they do use a different play style from what past players are familiar with and a couple of UI problems associated with the bahamut summon.