All scooters make electrical, motor and mechanical noises when they operate. They can also make a variety of road surface noises including rumbling and clicking. It's impossible to tell if the sound is "normal". As they break in and age, noises can change in pitch, volume or general sound. Where there was no clicking, there can be later. If the scooter is otherwise operating normally, you can presume that the scooter is operating normally.
All scooters we sell include our five year warranty which would cover a drivetrain failure. You can generally ride your scooter with confidence knowing that should there be an actual failure, it would be repaired at no charge to you.