Acquasanta 1903 (first 9) and 1913 (second 9). I believe anything else built in the timeframe you mention does not exist anymore (e. g. the course built in Sesto Fiorentino, replacing the earlier track in the Parco delle Cascine and later to be replaced by today's Ugolino). The next oldest, still existing course may actually be Villa d'Este from 1926 - I'm not entirely positive on this, but it can't be far off.
Ulrich