Kundalini creates heat, and makes you hot, in Sanskrit it is called tapas, when you create a lot of concentrated focus, stimulation, heat tension, or even stillness. These tapas transforms energy.
So it is best to do in morning as it gives high energy, mostly in kundalini yoga you will find breath of fire incorporated, and fast repetitive movements which are done in big numbers like 108. And yes it stimulates kundalini.
Hatha yoga is slow, breathing is not too fast, it is best to do in evening because it calms you, gives peace of mind, refreshes, for me it cures literally everything what I accumulated trough out the day. You go slowly while stilling your mind, watching breath, toughts, if you are advanced also observing energy, keeping body in one posture comfortably, I think you get what I am saying. It relaxes, and at the same time trains your mind, body, spirit.
This is most obvious differences I am able now to tell you.