I think that he was referring to his Manichaean phase of nine years duration and the works that he wrote then, not his Catholic works.
Augustine encountered Manichaean teaching soon after the impact of the Hortensius, and remained an adherent for nine years. In the Confessions he is concerned with the effect of Manichaeism on his own relationship with God.
All Catholics that I know understand that that all grace comes from God and that without His saving grace, we cannot have everlasting life. The Church has always taught that we cannot earn our way into Heaven.
All men here means all men period.