To be a better kicker, you need to be able to decelerate. Decelerating means you can put on the brakes, plant, cut and move, and change your body’s center of mass. Approaching the ball to kick, you have to be able to control the deceleration so your energy can go into your swing leg and thus into the ball.

For you to enhance your deceleration requires you to train with unilateral strength work. You can perform single-leg squats and barbell step-ups.

You can also do simple reflexive movements such as stopping drills to improve your ability to decelerate. Just make sure you start with the simplest movement to improve your ability to decelerate.

Having more mobility through your hips you will have a longer swing leg as a kicker. Enhancing your mobility will essentially lead to you having a longer lever to apply more force. If you are more mobile through hip extension and hip flexion, you will have more time to develop force which allows for a higher top-end speed to create greater velocity into the ball. 

Improving your mobility for your kicking means you have to perform the couch stretch, the hip 90/90, and the slow eccentric pigeon pose. A more mobile hip girdle increases your mobility and may help with preventing injury.

Dynamic trunk control allows you as a kicker to throw on the brakes and not fall off kilter. You can do unilateral side med ball throws or side lateral jumps with a kettlebell.

Finally, you need to focus on power and hypertrophy exercises. You need to make sure your legs get stronger, more explosive, and maintain structural integrity. You must do cleans, snatches, slow eccentric front squats, and back squats. 

You also need to be doing single-leg barbell squats almost all the time as a kicker. The single-leg squat puts you in a position with hip extension and the quad lengthened through the rear leg while focusing on stability and strength with the front leg. Doing 5 or 6 sets of 4 reps on each leg is great.