Is there a requirement with regard to a degree level? Can I apply if I have dropped out from the University?
Shortly - no, you don’t.
Tier 1 Exceptional Talent Visa in Digital Technologies differs from any other field in this visa route since it does not require neither Ph.D nor any degree to get it. For many other areas like Engineering, Science or Humanities - the highest level of scientific achievements is “must have”.
Literally speaking, you can finish your school and then have practice of work in the industry and then get your Tier 1 Exceptional Talent Visa based on this experience.
By the way, if you want to check your eligibility for Tier 1 Exceptional Talent Visa in Digital Technologies - go to the Quiz, created by Tech Nation. In my recent blog post I explain some of the positive aspects of it: http://aseleznov.com/tech-nation-visa-quiz/