Place the chocolate wafer cookies in a food processor, grind into fine crumbs. Add 1/2 cup melted butter and process with on-off pulses, just to blend.
Press crumbs evenly onto bottom and up the sides of a 9 inch pie plate. Bake at 325°F 10 minutes. Cool completely.
In small saucepan, heat 6 tablespoons of Kahlua and expresso powder over low heat until warmed and powder is dissolved. Add chocolate and 1 tablespoon butter. Stir until melted and smooth. Cool completely.
Transfer vanilla ice cream to electric mixer bowl and allow to soften slightly. Add 2 tablespoons of Kahlua and beat on low speed to blend. Spread over bottom of cooled crust and freeze until firm, about 1 hour.
Spread cooled chocolate mixture over ice cream in plate. Freeze until firm.
Transfer chocolate ice cream to mixer bowl; blend in remaining 2 tablespoons of Kahlua as above. Spread chocolate ice cream over sauce in pie. Freeze until firm.
To serve, whip the whipping cream to soft-peak stage. Pipe decorative the border with whipped cream around inside edge of pie.