I would choose garden view for 9 nights and use the extra money to plan a few date nights for the adults and Neverland Club for the kiddos. Garden views are lovely and you can watch the castle, fireworks, and EWP from the beaches. IF you could swing TPV, that would be the best. I just think lagoon view may be a disappointment for the money because you aren't guaranteed a castle view. It is lagoon view with a most likely obstructed view of the castle...otherwise it would be TPV category. IF you wanted to do 8nts TPV and 1 night moderate---go for it---esp if you are arriving late in the day anyway. You can just pack your overnight and 1st day clothes in the carry-ons to make moving resorts a breeze,
It is tough to request a certain longhouse in the garden view category because you aren't really saying "what" is really important and it is the biggest pool of rooms. If Tahiti isn't available, they have nothing else to base your request on. If staying garden view, request the area you want or floor...like... near TTC, or 3rd flr near TTC. *if* you are staying TPV, I would definitely say Tahiti please. There are only 3 longhouses for TPV(non-concierge) and the request will be a little easier to understand and accomodate.
I personally don't think club level is "worth" it for our family but others do see value. I would rather have a specific view or spend my money on extra made-to-order food vs snacks and apps laid out on a table. We order our beer, wine, water, and breakfast/snack items from gardengrocer to enjoy at our leisure without worrying about the time and sharing with other guests. IPO services--I make my own ressies(read control freak here) and don't need their assistance while on vacation either. Lobby concierge can help/answer any questions. Some like knowing their exact location/longhouse. I actually am in the minority here as I do not like that location. I would rather not be right on the busiest beach and next to the busiest pool. Again--personal preference here. For the money I would do either extra food(room servie/ Narcoose's/ blue zoo/ Artists Pt) or better view--TPV-- with a little extra food
Anyway you slice it, it will be a great trip. Have fun.