In Kevin's first 7 baseball games, he hit 5, 2, 8, 1, 6, 4, and 7 singles. In his eighth game, he hit fewer than 10 singles and his singles-per-game average for the eight games was an integer. Similarly, in his ninth game, he hit fewer than 10 singles and his singles-per-game average for the nine games was also an integer. What is the product of the number of singles he hit in the eighth and ninth games?