I dont understand why you prioritize fish over your set up. The fish dont deserve to be stuck in a poorly filtered tank with their own excrement. A 9 inch fish is not a small fish and will put out plenty of waste. Take a step back and stop riding the impulse train and get your set up perfected before you start buying fish you cant care for. Get the filter now, and the fish in 6 to 8 months. Honestly, if you cant afford a $250 filter in the next two to four weeks, you probably shouldnt have a large aquarium because it will definitely cost you more than you can afford. But ultimately I cant stop you, I just hope you take the time to get your priorities in order.