Hy, playing in the Open U10 category, secured 8.5 points after eleven matches for his second position in the final ranking.
The champion in the category, which saw the competition among 150 players, was M. Ilya from Russia with 9 points.
Hy was the only player among nine Vietnamese competitors to be named among the top three of the annual tournament.
Three other Vietnamese players were also listed in the Top 15, including Vu My Linh in the Girls U8 category, Dang Anh Minh in the Open U8 and Vo Pham Thien Phuc in the Open U10.
The 2016 World Cadets U8, U10 and U12 Chess Championships, taking place from October 18-30 in the city of Batumi, attracted nearly 730 players from 66 countries around the world.