The price for learning a new attack for Riolu (the juvenile Lucario) is 25 and 10,000.
But the Gamepress info sheet for Lucario says that the price for learning a new attack for Lucario is 75 and 75,000. This is quite unusual as most times (all the times) the price of learning new attacks is the same in both juvenile and adult forms.
Now,… I don’t have a Lucario so I cannot verify the accuracy of the info given on gamepress. But let’s say it’s true. If so, could I add the new attack at the juvenile form? Will it stay with my mon after it is evolved??