Honeymoon in Hawaii?

It really depends on what you like to do! Hiking? Fine dining? Water adventure? Exploring museums and historical sites? As you point out, there’s a lot, so I’d start by thinking about what you enjoy doing on regular vacations. I’d also plan an itinerary that balanced relaxation and activities.
I’d suggest narrowing down which island you want to visit first, if you haven’t already. And with only a week and a half, I’d stick with one island—Maui or Oahu would be my top picks!

FH and I are going to Hawaii for our honeymoon in October! So I can't help with personal experience quite yet, but we're planning on 5 days on Maui and 5 days on Oahu (will really end up being 4-4.5 days on each due to travel). I'd research the different islands and choose 1-2 that have activities that you'd be most interested in (for us, combination of relaxing at the beach and adventure activities). We booked a VRBO rental on Maui because the hotels there are sooo expensive but booking a hotel on Oahu since there's so many of them in Waikiki (very touristy, but also cheaper).

I’m doing 5 nights in Maui and 5 nights in Kauai in August. Staying at the Andaz in Maui and the grand Hyatt in Kauai.

We went when I was in middle school, so my memory is a little hazy. But, we did Hawaii specific activities and it was a lot of fun. We went to the volcano (you can hike to see the active volcano but we didn’t), Pearl Harbor, swan with dolphins, black sand beach, and a whale boat. We stayed at Kona Village Resort and it was really nice! Each room is its own little private hut! I’ve been wanting to go back but they got hit my the tsunami a few years ago and they are rebuilding. I think it was sent to reopen this year but it got pushed back. I’m not sure when it reopens but it’s worth looking into. If my memory serves me correctly meals were all included (not sure about alcohol as I was a kid) as well as beach activities like snorkels and kayaks. They had hula lessons and classes to make your own leis and hula skirts. They also did a luau (not sure if that was included or extra).
Have fun what ever you decide to do!

Thank you for the suggestions! I haven’t done my research yet into which part of Hawaii would be best to visit but in terms of activities, we’re looking to lay low and relax for the most part by a beautiful beach/pool with drinks in hand and then maybe do a little bit of exploring the island like some nice walks or hikes. We’re looking to stay somewhere that’s nice yet also affordable (and good food would be a bonus for my future husband!)

We just booked 10 days in Oahu! We're staying at the Hilton Hawaiian Village (full disclosure: my parents are Hilton Vacation club members and gifted us some of their points from last year because they won't be able to use all of last years before they expire). But the hotel looks gorgeous, it's right on the beach, and from what my parents have told me there is a TON of stuff to do on the property and nearby. Plus, all the standard touristy activities.