Unfortunately, you need to first accept that you have a role your boss want you to have. Then, stop the "resistance" and go with the flow if you still want to work there.
Some workplaces are like the one you described; your role might not be to do the best work ever but to simply create a concrete result of the "vision" of your boss. That might not be a place where you will perform; that might be a place where you'll make money, gain negotiation skills, and experience though. It's useless to fight against this but learning how to share your ideas and get them approved is also a very great skill to learn; you're in a place full of that kind of challenge and see this as something positive you'll gain from this experience!
If you do resist this atmosphere in the workplace, you will be put in a very bad position and might even get your colleagues against you... which might lead to sabotage, rejection, bad reputation, etc. And ultimately, you will get depressed or even burn out.
The other employees who go with the flow might have simply accepted to be mediocre and/or might simply work for the money or there's a detail you're missing about yourself and that you can improve. Simply put, you're maybe the only one working with that goal in mind and this can happen in places where that kind of mindset has been there for years or where older employees mold the new ones. It's also possible they're simply better negotiators than you and know how to not get too technical when presenting a project; lot of very smart and skilled people have hard time presenting their ideas and what's obvious to them isn't to others. Sometimes a little bit of neuro-linguistic helps a lot! There are lot of factors why your ideas are not implemented. It could even be the good old patriarchal sexism if you're a woman or because of your young age, and these are all things that are hard to change but it's not impossible to prove your value even with these obstacles.
If you really have shown numbers, stats and REAL benefits, and if your ideas were still refused than there's not much more you can do on that side. Either there's a communication issue with the dev where you work or you really are in a place where employees don't cooperate. What will make your boss change his mind is to prove him your ideas will make him earn/save more money. It's that simple.
You have at least 3 options:
1) you implement your ideas without the consent of your boss and then deal with the consequences/benefits (if it works, boss will gain trust in your judgement). I know #1 seems like a risky advice but sometimes being a rebel is necessary and that's also the source of all innovations.
2) you start looking for a new job.
3) you can see if there's a way to build a better collaboration with the dev team or the other departments; build your projects by asking more feedback before going too far, there's more chances they will be implemented. It's totally normal that your suggestions aren't always accepted 100% and it's even harder when working with a lot of colleagues doing different functions. At some point you'll figure out a formula that works well with the boss and team, and your success rate will increase.
It's possible there's little chance anything will change; it also depends on how much you like the projects you work on and how much energy you want to put in solving your issue. The ambiance at a workplace is often a reflection of the boss attitude and you know the boss is there to stay. Sometimes, the boss has simply no clues and you need to find a way to speak the same language as him or her (eg. usually money.) But communication with the other departments can always be improved. As much as you want your ideas to be implemented, the dev also have their self-interest in this. Find it and make it happen.
8 months is not such a short term and if you think of quitting, it's better to quit while your moral is good than hope for something better to happen at the workplace! In fact, some companies have a bad reputation, other employees before you went through the same thing you're going through and they obviously found new jobs where they got hired; even without knowing it, competitors often know about all this. Quitting now therefore shows self-respect and doesn't brand you as being like the people at the company you work for.