I have three of the whisper filters, 2 that came with my five gallon kits and one just like the one you have for my ten gallon. I like the ones that came with the kits because they have a high/low flow switch on the back. One of them is silent and the other makes a constant vibrating noise :/ I have found that my 10i has a too strong of water flow for my liking so I baffled it.
Also, I'd do more research on live plants. He really needs more decor and those plants will need some kind of nutrient supplement like Seachem Flourish. There are many easy beginner plants that are known to be safe for bettas. I have personally never seen anyone recommend a banana plant as a beginner plant.
EDIT: also if you currently have no hood on the tank I would cover it with something until you get one. You wouldn't want him jumping out and getting injured.