Complex sentence: High School football is a popular community event; the Monticello Billies won the AAA (now AAAA) state championship in 1994 and in 2009 and the Junior Billies (from Monticello Middle School) were undefeated in the years from 2005-2008.
Split into simpler sentences: High School football is a popular community event; the Monticello Billies won the AAA (now AAAAA) state championship in 1994 and in 2009. And the Junior Billies (from Monticello Middle School) were undefeated in the years from 2005-2008.