I feel this is the strongest statement made so far. It is the raw truth of Go. You need experience, heaps and heaps of personal experience, to progress. Most things in life allow you to study hard and gain a huge advantage in the realm of progress, once you begin your journey. While this can be true for Go to a degree, there is an element to learning it that only real life experience can uncover.
This information is already in the Newcomer’s Guide that I linked you to in your game review thread, but I feel it warrants mentioning again. There is a really easy and solid way to learn where to go:
At It’s Core, What Is Go?
Something that is really important to realize about Go is that, no matter which board size you play on, it is an exercise in pattern recognition. Go is not about winning or beating opponents. The game, in my view, is a solitary pursuit. For we only ever truly face ourselves. Each game is essentially a unique puzzle, being generated based on our decisions and our opponent’s choice of moves. Your opponent represents chaos, the unknown, or randomization; not a foe or force to be overcome.
Rather, Go is an exercise in memorization of shapes and how to employ and counter them effectively. Especially considering how the methodology of countering the same shape changes based on the surrounding board configuration. The myriad of possibilities in any given game with familiar shapes and patterns is breathtakingly complex. To this end, you should realize that the only true way to get better is to build your brain’s database of shapes, patterns, and how to properly employ and counter them.
This can only be achieved through raw experience. Maintaining mental focus while studying specific topics of interest, searching for weaknesses in your understanding through self analysis and third party analysis of your games, and deliberate practice will accelerate your speed of progress. It is also likely to teach you lessons or reveal aspects of Go game play that you would otherwise never stumble upon yourself.
Learning Go Openings is essential because the framework that is built prior to the Middle game, literally determines the possibilities during the MIddle and End game. If you play poorly during the Opening segment, it won’t matter how crazy your Middle or End game skills are, because you have likely already lost.
The Opening is crucial for establishing a framework of territory large enough to secure victory; akin to sketching Blueprints for a structure. During the Middle, those Blueprints are largely filled in and all the major features are decided. Huge shifts in the design can happen here, but they tend to occur, almost exclusively, within the already established framework already on the paper. The End game is where all the lines of design get finalized and set in place.
Points wise, very little tends to change in the End Game. All of the major action happens in the Middle. If your Opening was poor, you won’t have much to work with. If your Middle was poor, the End game won’t much, because you’ve already lost. If your End game was poor, it won’t matter unless you guys were pretty close in points when you entered it. Well, assuming that there were huge vulnerabilities in your shapes that your opponent can exploit. So starting with the opening makes a lot of sense.
Please note that my advice on Openings pertains only to the 9x9. They are crucial to victory on the 9x9, and are nowhere near as complex or numerous as on the 19x19 
I wrote a guide on the difference between both rulesets. It includes a breakdown on the differences between scoring in each ruleset: What Are The Differences Between Japanese, Chinese, & New Zealand Rules?