If the person blowing the Shofar (ram's horn) on Rosh Hashanah needs to eat something before the blowing of the Shofar to give them strength to blow the Shofar properly, it is permissible for them to eat even cake, even bread, and things that are mezonot (grain foods) before the blowing of the Shofar. It is proper in that situation for them to make Kiddush (sanctification over wine) first. They don't have to; it's not a requirement, because technically the Chiyuv (obligation) of Kiddush doesn't set in, according to most poskim (halachic authorities), until after Musaf. He hasn't prayed Musaf yet, but he says it's appropriate for the person to make Kiddush if they have the ability to. Then they can eat something. After Musaf, they would make Kiddush again, for those who say that the obligation re-enters after Musaf, before going ahead and eating their meal.
The same would be true for anybody who felt weak or wasn't able to concentrate or focus during the blowing of the Shofar. If they don't eat something, they should make Kiddush, eat, and then make Kiddush again after Tefillat Musaf before going ahead and eating their meal. Women, of course, who are not obligated to hear the Shofar but are coming to the Beit Knesset (synagogue) to hear it, can eat beforehand because they don't have an obligation in the mitzvah (commandment) anyway. But they, too, should be careful to say Kiddush, given that they're not obligated in the mitzvah. And so the obligation for Kiddush may have set in if they don't usually pray Tefillat Shacharit.
However, he says that it should not be a custom for the entire shul to pause the prayers for everybody and go have a whole Kiddush and a breakfast that everybody eats before the blowing of the Shofar. He says that if a person needs it because they're sick, need to concentrate, or need the energy to be able to do it, then they should be able to do it, and that's fine, but they shouldn't have an entire break. That being said, it is appropriate for a person to try to at least drink something in the morning, such as coffee or water, or have a sucking candy or something, to make sure they're not fasting. The prayers are very long, and if a person doesn't eat or drink anything until after midday, then they would be considered to be fasting for more than half the day, and we're not supposed to fast on Rosh Hashanah.