Conner was not completely housetrained until he was almost 10 months old. We went to Florida when he was 9 months old, and I got him belly bands to wear in my mom's house (she has white carpeting).
I don't know if it was the belly bands (which he hated) or seeing my mom's yorkie going potty outside, but while we were there he never had an accident and has not had one since (he is almost two). Just keep on top of it - he will get it eventually. Now Conner would be mortified if he had an accident. He is always so proud of himself for going outside.