Preheat oven to 325. Make pie crust by combining cracker crumbs, sugar, and butter. Press crust mixture into a pie tin and refrigerate until ready to use. Heat milk in top of double boiler over simmering water. Mix sugar with cornstarch and whisk into milk. Add lemon juice, zest, and vanilla and blend thoroughly. Pour mixture into pie shell. Bake for 25 minutes in middle of oven or until set. Cool pie for 10 minutes. Melt marmalade over low heat and brush thin layer over surface of pie. Arrange kiwis in overlapping layer to cover top of pie completely. Brush again with remaining marmalade and cool before cutting.