Lots of good advice in the details below. But there are some hard truths I need to tell you...

I think you are making multiple - and serious - basic, bedrock mistakes. If it's any consolation, they are the same mistakes that most first-time travelers (and travel blog followers) usually make. Ignore my advice if you like, but I've been at this a while and I think you are going to need to re-calibrate at least some of your expectations. Here are the issues I see...

1. You are trying to do too many places in the time you have (or, if you prefer: Your trip is just too short.)
You have 9 days for your trip, end-to-end. That means you have about 6 full, usable days once you get there and recover from getting there. Do not discount the "recover from getting there" part. It consumes a day just to get there, same for getting back. But you will be wiped out upon arrival, from all the pre-trip stress, the actual time in transit, jet-lag, and the confusion/disorientation of suddenly arriving in a strange, foreign country where everything is different. Language and cultural differences, getting lost, etc. etc. It certainly helps to fly in a nice F or J seat, but the travel does take something out of you. On your first trip, especially so. Most folks need a day (sometimes more) upon arrival to get back up to something like 100%.

The best fix for this problem is to take a longer trip. Personally, I don't think it's worth it to go to Europe for such a short time - 2 weeks would be my suggested minimum. 6 or even 7 days is just not enough time to justify going all that way.

You can mitigate this somewhat (though not completely) by limiting yourself to just 1 or 2 destinations. Remember that every time you pick up and move to another location, you will burn the majority of a day (don't figure flight times, that's not being honest: getting out of a hotel, finding your way to the airport, security, etc, arriving, finding your way, getting lost then finding your way again, checking in, exploring the new place, eating, etc. - all these tasks add up and consume your day). With 6 full usable days, you should stick to one (MAYBE) two locations - I'd suggest one, with possible day-trips out and back.

2. It is extremely unlikely that you will get the beautiful F or J seats you are visualizing. Not impossible, but very, very hard in the real world. Ignore what the dishonest bloggers want you to think - their rosy scenarios are perfect-world, limited and generally unavailable options (eg, book that F seat 3 days before departure when it suddenly pops up, but there's only one seat not two, etc., etc.). Be honest with yourself - start now to look at dummy bookings for the flights you are eyeing (for both of you). How's that availability look? The dirty little secret of this game is that getting the points is the easy part - using them, for optimal redemptions under the ideal conditions you want is more than hard (unless you're willing to live like a blogger - book 2 days ahead, one seat only, and don't be picky about where the plane is going). But if you have to nail down your time off work months in advance (ie, you have an actual job), the options are very, very different from what the bloggers tell you.

3. Don't lose perspective. Don't let travel blogs/FTers and other fools who make their living by inducing points envy convince you that your trip is actually about the airport lounge, the big name chain hotel, or the warm nuts in a bowl served in the seats up front. Yes (of course), luxury frills are nice. So is getting a "free" room (or flight) - and yeah, I like them too. But those things are NOT what travel is about. If you can leverage your points to get a nice room in a place you would be going anyway, great. But too many people let their hotel and airline points drive where they go - and that's absolutely crazy. Go where you dream of going, and figure out the best way to book your rooms after that.

You say you're open to "any destination." That suggests to me that you haven't put much thought into what you like to do/see/experience (ie if it's all pretty much the same to you, then why bother going anywhere?). Set aside all the fantasies of luxury hotels and premium airline cabins for a bit, and ask yourselves the much more important questions about where you actually want to go. What if you never got to travel overseas ever again after this 6-day trip? (That might sound impossible here, but believe me, things change, life happens, and for lots of people that is their reality.) On your deathbed, what would you regret not having experienced? The Park Hyatt hotel in Sydney? Seat 1A on a LH 747-800? Or seeing the setting sun reflected on your love's smiling face from the top of the Eiffel Tower? Priorities...

That's enough from me, I'm sure I'll be eviscerated in the next comments.

Good luck, make smart choices, and have fun.