Echoing much of the above....
Training for a first marathon is all about discovery. As you start on the path, you think it's about the miles, only. But its also learning about hydration, fueling, clothing and many other do's and don'ts. You will learn what you can and cannot do as you start to add miles - your will learn the mental side of the game as well.
First, sounds like you need to pre-run fuel a little earlier. I would not have solid food 60-90 minutes pre-run. This time can vary but this is a good starting point. Likewise, I am not sure about the hydration strategy, but you cannot drink enough water pre-run for a 9 mile run. Plan on carrying water while running. You have overdone things if the gut is sloshing and once that occurs on the run, the gut has essentially shunted, meaning that it will not process any further until you slow up on the intensity.
Next, if you are not wearing tech clothing, get some. It is pricy but cotton is an absolute no no for any serious runner. And YES, you are a serious runner if you are training for a half or full.
Next long run grab some runner's lube and apply where chafing occurred. Most runners will have a little rubbing and this is a great way to limit the effects.
As mentioned, slow up in the heat. If really hot, you may need to add 2-5 minutes per mile. Going out too fast too soon will lead to a shortened run. Part of training is learning pace and how to judge your pace as you run.
Finally, the mental side of the game is huge. The mind is extremely powerful and can convince you to not run.... even on a great day. Overcoming these negative thoughts while on the run is one of the largest parts of training. Many folks never figure it out. I can assure you that if you learn the little mental cues that give you the work around to the "I must stop" thoughts you will do well in the race.
So what's next. First of all, try again today if possible. If not, just make your next scheduled run on Tuesday (assuming Galloway plan) and hop back on the plan. For the next long run, if you get the feeling of needing to bail, just walk for 5 or 10 minutes then restart. That may or may not work, but sometimes breaking up the run can work wonders. Do not beat yourself up just yet. We all have bailed on a run and have made the race.