I do agree with the horse being young, he needs miles under saddle to learn to be braver.
I got my mare Spice when she was 3yrs. Old and only 30 days of riding. She was my first horse after 30 yrs. Of being away from horses. Her and I spent alot of time in the roundpen working on gaining each other's trust. I did alot of desensitizing which really helped her with trusting my judgement on things. You've got to put the time in doing ground work and then putting miles on the horse. Spice is now 10, she spooks very seldom and when she does she doesn't panick but waits for my direction.......it took alot of miles and alot of us spending time together to get where we are today.