I knew the station I was going to but still got lost. Having a map and pointing to the station name as I asked folks for help was incredibly effective at getting back on track, even if we never actually spoke the same language.
As for what to do, wake up early,
go to Tsukiji Market. Have sushi for breakfast. Both the cheap and the upscale places around the market are pretty good, though very different experiences.
I actually did both one day just because. Head back to your hotel, grab a shower and head back to the airport.
On that first day, with the 9am arrival, you can probably get to the
Imperial Palace and then wander around the Shibuya neighborhood to get a feel for two very different parts of Tokyo culture.
I did my trip in 50 hours, not the ~30 that you'll have but I think that the general plan would still work pretty well.