As I said a moment ago:
-They likely didn't have the budget to wholly fabricate an entirely new 9th house. You can say Universal should've given A&D a bigger budget, but they worked with what they had.
-Those puppets were expensive, and to order them, A&D probably promised they'd get some mileage out of them for X years.
-Worth noting that apparently the layout won't be exactly the same - there will be tweaks and maybe some upgrades.
Given these circumstances, A&D almost certainly figured - look. We can't build a quality 9th house with the money we have. Let's tweak one of our favorites - and one of our fan favorites. We still have all of the materials. It's a "bonus" house in addition to the new 8 houses we're getting.