You did not mention where in Dublin you were staying. If you are near Trinity University you could get in line and be one of the first to enter the exhibit for the Book of Kells which opens at 9:30, if that interests you and also take a look around Trinity University. You could walk along Grafton Street and see the Molly Malone statue and take in the ambiance of Grafton Street. Bewley's Oriental Cafe opens for breakfast at 8:00 am and is located on Grafton St. There is also a Starbucks on Grafton St. It is located on the 2nd floor of a department store-can't remember the name. If are near O'Connell St. you could see the Ha'Penny Bridge and the famous Post Office. I think taking a ride on the HOHO bus would be a great way to get a quick look at Dublin, but I am not aware of any 30 minute ride/tours on their buses.
When we were in Dublin last year we looked for a place to eat breakfast near our hotel before our early morning flight and noticed that some restaurants and some coffee shops do not open until 8:30 or 9:00. We settled for coffee and a scone at a coffee take out place across from our hotel. There are quite of few of the take out coffee shops along Nassau St. which is near Trinity University. My daughter found a restaurant/ delicatessen on Nassau (she said they make the best sandwiches in Ireland!) and we ate there for breakfast once. It is called KC Peaches. We noticed many Dubliners having breakfast there as well. It opens at 8:00.
I think the Pub tours usually start at 7:30 PM although there may be later times as well. You will have no problem finding a Pub and enjoying some music in Dublin. I'm not familiar with Pubs in the Temple Bar area so maybe someone else on this site could answer that question for you.
Enjoy.
Barbara
