I recall this question was asked somewhere on this forum. Brant Chambers' best this was 9.4 in Round 15. The last time a century goalkicker did not kick at least 10 goals in one match was John Roberts in 1987:
Year Player Total; Best
2007 Chambers 112.35; 9.4
1996 Hodges 116.54; 11.3
1994 Hodges 129.51; 11.3
1990 Hodges 153.81; 14.5
1990 Jakovich 101.68; 13.3
1988 Nichols 104.31; 13.6
1987 Roberts 111.45; 8.2
And the same stat for the other century goalkickers I have in round-by-round detail:
1986 Nichols 103.34; 10.2
1985 Blight 126.69; 14.0
1985 Willmott 112.42; 14.4
1984 Evans 127.48; 9.2 - another instance
1984 Dietrich 101.42; 12.0
1983 Davies 151.69; 15.3
1983 Roberts 112.37; 11.3
1983 Dietrich 109.47; 11.4
1983 Luders 105.62; 11.4
1982 Evans 125.54; 10.2
1982 Pierson 109.38; 11.0
1982 Edwards 104.55; 11.2