PSA: Wii Shop purchases don't get Club Nintendo coins through Wii U
This is because you can't link your Club Nintendo account to the virtual Wii within your Wii U, which you'd use to buy legacy games.
The easiest solution would be to buy whatever you want on Wii, and get the Coins, before transferring your Wii data to Wii U. But if it's too late for that, you have the choice either to buy on Wii U and forfeit the potential Coins, or realize it's 2013 and that you've likely been pretty much caught up with WiiWare for the past two years, with the possible exception of La-Mulana.