No wonder you are hesitant as they recommend a 6 inch distance to the canopy is for 1085 microMoles. Using the inverse square law of light at 9 inches that is 485 micoMoles and at 12 inches you are down to 271. If there is little or no InfraRed radiation (heat) then you can run those lights at 9 or 10 inches above the seedlings. The thing you want to do is make sure there is no IR by holding the back of your hand to the light at 9 inches. Move around a bit to test the light over the length, Is your hand comfortable? If yes your plants will be also. During flower you are going to want to run at 9" or closer.