You could buy a day pass for Zurich Airport to Kilchberg. This is valid 24 hours and includes Zurich city. And another ticket, Zurich to Lucerne. Go to sbb.ch, and enter Zurich Airpiort to Kilchberg, full fare, return. CHF 17.60 per adult.
Luggage can be deposited in lockers at Zurich main station and taken with you when returning from Kilchberg. Luggage check-in would be possible, too, but the luggage will only arrive in Lucerne two days later which, I think, is not in your sense.
Without knowing your complete itinerary, it is difficult to give advice. The Swiss Half Fare Card or the Swiss Travel Pass could be great deals if you plan on visiting our country for multiple days. So if you want a more elaborated advice, you should not mention fragments yet your complete itinerary. Also, the question is, whether you travel with children as there are special family and children offers, too.
Furthermore, voluntary-operated travel forums, such as myswissalps.com or the TripAdvisor Switzerland forum, can assist in the planning of your trip to Switzerland. Meanwhile, we remain at your disposal for all ticket queries for which we are the experts.