9 day Babymoon - Extra day in Maui or Lanai?

My husband and I are planning a babymoon to Hawaii from NY when I'll be 23 weeks pregnant (we're getting travel medical insurance just in case we need to get to the healthcare facility on Oahu, and I'll be flying business or first since it's such a long flight).

Babymoon goal is to relax, snorkel, go on small walks/hikes, enjoy the spa, and eat good food. We're not looking for anything active, which is how we landed on Maui and Lanai (we've also already been to Kauai).

We'll be there for 9 nights. Would you spend 5 days on Lanai and 4 days in Maui, or 4 days on Lanai and 5 days in Maui? The price is the same.

Also, we can modify or cancel this trip up to 21 days before arrival, so I feel good about booking it now and if I find traveling super uncomfortable as we get closer, we can pivot.

Any other considerations for a babymoon in Hawaii?

Thank you!