The bus might be worthwhile if we just miss the MXP train to Centrale, so that we wouldn't have to wait 30 mins for the next train, although I worry about traffic. We are scheduled to land at 8:10 on a Tuesday morning.

The train from Centrale to Padova seems the clear choice for getting to Padova. We'll probably gamble and buy tickets soon on the 11:45 train, as it's much cheaper in advance and trains sometime sell out if you wait until the last minute.