I don't understand your use of "through iCloud" above. If you think your music is in iCloud, then you must subscribe to iTunes Match. If that's true, then go to Settings > Music > iTunes Match and turn it "On".
I've got my music stored on my pc. If I purchase music on my iPhone, my wife automatically gets it on her iPhone too. I've purchased an album on my iPad and it wasn't in my music. It just states there is no music. I download purchased albums via iCloud and they never appear in my music