Yes, you can. I heard that the restaurant is very good and it is cool to visit and try to eat their delicious food there. That restaurant serves lots of Japanese foods that are new to the restaurant. I hope I can visit that restaurant soon. It is important to eat in the best
restaurant so that your payment is worth also.
I guess this depends on which country the restaurant is. It's always assumed that in the big cities of the United States you can always get any item of food or drink you want, and soda being popular, it's likely that even their Japanese restaurants can supply this.
Outside of the US, it might be sensible to expect Japanese food and drink in Japan, and if you seek a Japanese restaurant, the expectation would be that you wish for their own food and drink, not American ones. I guess you can get soda in their large supermarkets and that there may be tolerance for restaurant customers bringing in their own drink, if, like medicine, they cannot contemplate a meal without their soda.