Texas does not allow 8th graders to compete in varsity spring softball. It is an urban legend that 8th graders may compete in varsity softball but sacrifice one year of eligibility if they do. The applicable rules are found in Section M (Section 400) of the UIL Constitution. Only over-age 8th graders (more than 15 years old) may compete in varsity spring softball (Section 1478).
http://www.uil.utexas.edu/policy/consti ... 08subM.pdf 8th graders may compete in fall high school leagues not coached by the high school coach. This actually is quite common throughout the state.