Nope, you should not do that, it is risky. It is a widely known that contact lenses or eyeglasses are not allowed to wear in intense exercises, especially on sparring sessions. The most important reason is there is unexpected incident during the process. For instance, when you are doing a kickboxing exercise with your partner, unfortunately, you get hit in the face. It is high risky for your eyes to get injury because of your contact lenses, maybe damage your retina. On the other side, kickboxing is a sports between two persons in a square place, your partner is not that far away from you, thus it would not affect your eyesight to find this person opposite to you. Additionally, they are easy to fall out while sparring, so it is really annoying and make you could not concentrate on your sports. Hence, it is not advisable for you to wear them when you are kickboxing.