Vadillo was born in Puerto Real, Province of Cádiz, and joined Real Betis' youth system at the age of 12. On 28 August 2011, he became the second youngest ever player to appear in a La Liga game, as he started in a 1–0 away win against Granada CF at the age of 16 years, 11 months and 16 days.[1] The previous season, he contributed with 14 matches (one goal) as the B-team narrowly avoided relegation from Segunda División B.