Totally understand your thought process. Unfortunately you need to move both the top and bottom teeth to achieve your goals. Most likely your top teeth have moved due to the crowding of the lower teeth. Your lower teeth drift forward due to biting forces. Your top teeth are essentially parallel and your lower teeth pivot near your ear. So the force on your lower teeth id down and forward causing them to move forward. Well if the lower teeth shift forward your top teeth get pushed out of allignment to accommodate during chewing. Now with adult Clearcorrect you make room by interproximal reduction. This is when teeth have a small amount of enamel (outer layer of tooth structure) removed. This amount of removal is about 0.15 mm of structure on treated teeth (very small amount) which should not cause additionally sensitivity. Studies show that the enamel layer has a thickness range: 0.44-1.28 millimeters.
It is very difficult to diagnosis you situation with the limited information. If the appearance of your gums are not uniform on both sides of your mouth I would be suspicious of pathology. When I say pathology it could be related to infection or other changes to the tissue. My recommendation is to make an appointment with a dentist to complete an examination.
In your question, is it your right front tooth that is crowned? What do you not like about your teeth? From your photos what is the discoloration you are unhappy with at this time?
There is no need to cover your implants when your dentures are not not in use. If it is uncomfortable to have the attachments of the implants exposed, you need to review this with your dentist. If you feel more comfortable wearing your denture at night, then it is necessary to keep the dentures out at least 6 hours per day. This can be done when you are home in the evening watching television or reading. During that time, clean your denture with soft toothbrush and store your dentures in water or, better yet, an alkaline peroxide-based solution made for this purpose. Brush your gums and tongue every day with an extra-soft toothbrush (not the one you use for cleaning your dentures) or clean them with a damp washcloth.
Unfortunately there will never be ONE answer to a treatment. Every dentist has different training and opinions on the "Best" treatment. So this is my opinion only and if you dentist has a different opinion it is OK. 1. Since you are only 23 years old I would be conservative in my treatment. In my opinion I feel you should start with the internal beaching and bonding. You stated that 9 years ago you had trauma to the tooth. Just like getting a bruise on you leg, you hit your tooth causing damage to the blood vessel inside your tooth. At a young age your pulp chamber (hollow space inside your tooth) is very large. When the provider did the root canal he might of left some blood product in the upper portion of this hollow space which dentist call pulp horns. Blood product is broken down into bilirubin which stains the tooth from the inside. Internal bleaching will breakdown the pigment to small enough molecules that diffuse out of the tooth, or to those that absorb less light and appear lighter. After the correct color is achieved your dentist can bond to increase tooth height. 2. Crowning or Veneering the tooth is initially a great option. Unfortunately I have learned that all things eventually change. Meaning the teeth next to this crown or veneer will change color as the years go forward. So when I do crowns or veneers in the front of your mouth I suggest you always perform this procedure in pairs. The human eye looks for symmetry. If you crown the front right tooth you will eventually need to do the front left. So just a heads up on possible future treatment.