 Kunyange zvazvo akaberekerwa muSydney, Cahill akanga agara kuWestern Samoa kwemakore matatu asati adzokera kuAustralia achiri mwana. Football Federation Samoa yakakoka Cahill anogara kuAustralia kuti atambire nyika pa1994 OFC U-20 Championship. Vakundi vemakwikwi vaizokodzera nokuda kwe 1995 FIFA World Youth Championship. Cahill akaita kutanga kwake kwechikwata chepasi-20 pazera remakore gumi nemana. 