it possible a day visit from L'Hotel Causeway Bay in Hong Kong to macau?

Yes, it is possible to do it in one day.
From your hotel, you can walk to the Tin Hau Station to take the Island Line to reach Sheung Wan Station, where you can walk to the Hong Kong Macau Ferry Terminal. At this terminal, you can take a ferry for Macau.

In Macau, you can visit the Fisherman Wharf, the Macau Tower, the Ruins of St. Paul, the Senado Square, the Museum of Macau, the A-ma Temple, the Venetian.