Much Ado About Honeymoon...

I’m French, and there are plenty of French regions that are nice in September.
You could definitely look into the French Riviera/Provence region which is warmer and sunnier climates (without being hot or humid in September). Look into Nice, Cannes, Aix en Provence, Avignon. This is right next to Italy so you could still take a day or two to go into Italy, I wouldn’t worry about crime that much, just be careful and keep your purse near you at all times (this is true in most countries tbh).
The other side of southern France is super cool too like Bordeaux, Bayonne, Toulouse. Great place to do some wine tastings too. And you’d be at the border of Spain if that country interests you.

Also, one of my friend did their honeymoon in Croatia and loved it. I’m not sure what their weather is in September, but they have nice beaches as well as a lot of history. Might be the best of both worlds

I loved in Turkey for a while, it’s a wonderful place for a honeymoon. We took a couple of weeks and drive down the southern coast and stopped wherever we found interesting. There are ruins everywhere, everywhere. Many were not developed, just literal ruins in fields. We were often the only ones around.
We also went to some of the small Greek Islands, those were lots of fun too.

We loved Monaco and Avignon!

We're planning for Hawaii in October and from what I've gathered it definitely has something for everyone. We're also not sit on a beach for 2 weeks straight people (I love the beach but would feel like I needed to DO something to not waste a trip) and Hawaii honestly seems the best of both relaxing and adventure worlds. I know after all the planning and then the wedding weekend we will def want to relax so beach and spa days will certainly be on the itinerary but we're also planning to visit the national parks and go hiking probably rent ATVs or mountain bikes or something too.

Also I've been to France and Italy without knowing the language (practiced basic stuff to get by and used duo lingo app) and as long as you are respectful of the language and try before blurting in English people are very nice and many speak English too. The south of France is incredible and I was there in September and it was very warm and sunny definitely not melancholic. I was in Paris that same trip in September and the weather was very nice in my opinion. The Greek islands are also beautiful that time of year. I wouldn't worry about crime too much just be aware of your surroundings but that is the same in the US as well. If you're really worried you can get a purse with a chain strap that isn't easily cut.

Cruises are great for honeymoons! You can choose one with stops that interest you and you can try different excursions. They can also steer out of bad weather. Right now, cruises are having a rough time because of covid, but they should be operating on a normal schedule before Fall 2022.

Hawaii is wonderful for both people who like beaches and are also adventurous. When I went to Hawaii we did a cruise, so we went to multiple islands, but I'm also not a sit on the beach type of person and I found a lot to do. Depending on what you're into, they have all kinds of adventure tours and also more historic/traditional tours. We did a coffee, chocolate and vanilla tour. While some of it was kind of boring, it was interesting to see how each was made in Hawaii. They also had helicopter rides and other water activities that you could do so you aren't just sitting around.

As far as both Italy and France, I've been to both. For Italy, really the worst places for crime are bigger cities like Rome and Florence, and they aren't even that bad. I got a little thing I could wear around my neck and tuck into my shirt to keep any money, ID cards, etc. in. You could always wear something closer to your body so nobody pickpockets. Tuscany is a little less citylike, but absolutely beautiful if you prefer to visit somewhere not in the cities. Otherwise, Rome is really interesting to visit and I highly recommend. A lot of people in the more touristy areas speak English there, so you can usually get around fairly easily without knowing the language if you stick to those areas. If not, use one of the apps on your phone to translate! I've only been to Paris in France but I LOVVVVVEEEEDDDDD it! I've been twice. Same with the language, if you stick to more touristy areas then you can usually find someone who speaks English. Even with weather being cloudy at times, I don't think Paris is EVER really dreary feeling. I went in the dead of winter and we still had some really nice sunny days, plus the city itself is just alive and wonderful. Ugh, I love Paris so much.

South of France/French Riviera is beautiful in September and it's usually very sunny there. I think more than 300 days out of the year are sunny. There are lots of cities/towns/villages to explore but you could also probably find some beautiful beaches if you want a relaxing day.

Italy is a huge country and 'crime rates' are going to vary greatly depending on where you go, just like any other country. Just be vigilant. There are so many beautiful areas of Italy including Venice, Lake Como, Cinque Terre, Rome, Tuscany, Florence but my absolute favorite is the Amalfi coast. Beautiful towns, landscape and weather. There is so much to do and it is close enough to Naples, Sorrento and Pompeii for even more adventures. Also, many people speak English in the cities, resort towns and touristy areas. Many tours are available in English as well. Good luck!