Booking Tours

Do you think it is best to book tours online from home or to do it from our Concierge at our hotel (Sandos) when we get to Playa in a few weeks? We plan to go to XCaret, Cozumel, visit ruins, snorkel the reefs, jetski, swim in cenotes, and more but time is limited to just 8 days! Which ruins do you think we should see and why? (We do not want to spend a whole day getting to the ruins and hanging out there.) Should we take a bus or a tour to get to Tulum if those are the ruins we choose?

I hear that there are fewer visitors than normal so maybe we should wait until we arrive to make sure that the tours are still available as some places posted on the web are stating that they don't offer some of their tours anymore?

Thanks for your help!
Bonnie V.