Ferrara

Yes, there's time. I'd try to catch the 8:30 daily direct train that gets to Ferrara at 9:30. Later departures take longer and require a change of trains. There are plenty of direct trains continuing from Ferrara to Venezia S Lucia station.

The next question is where you'll leave your luggage. The train station may not offer storage, in which case, you'd have to try asking at the tourist information office or a private businesses.

I'm quite intrigued as to which private businesses would accept luggage from an unknown source in times of high security concerns? Is baggage scanned?

David, I'm nearly certain a bar/café outside the train station in Siracusa (Sicily) had a sign, indicating that it would store baggage. I think perhaps I encountered a second such place in Italy, but I'm not sure. I also threw myself on the mercy of desk staff at a 3-star sort of hotel in Viterbo that happened to be located near the train station. I had a 5-euro note in my hand, and it wasn't the sort of place you'd think terrorists would be interested in. Also, I'm a female senior citizen of Anglo descent. Who knows how many of those factors were critical--aside from the 5 euros, that is.

I did the same thing at a bar in a small Spanish town, where they ended up refusing to accept my tip, insisting they were doing me a favor rather than a service. (I bought a Coke.)

I'd never count on being able to store luggage anywhere without having found current, confirming information online. You have to take a chance and be prepared either to drag your luggage around with you or to skip the local sights you planned to see and get back on the train.