My 8 year old will be meeting her bio dad for first time. Where should this take place?

There is no should. I personally think 8 is old enough to be part of this decision. You discuss it with her, you discuss it with him, you make the actual decision.
I would pick a nice outdoor cafe in mid afternoon.
There you are semi-surrounded by the safe feeling of other people and she doesn't have to show too much interaction that she might not be ready for the first time.
And you can all get up and leave easily, without even waiting for a bill.

I would also add, if you and the father have issues, you and he are not the issues of meeting. So at times having a 3rd party do the meeting is best. If there are going to be personal issues involved.

Have you and the bio father had any contact or interaction in those eight years? What was the relationship like before and during those 8 years? All these are important things to consider when/how you bring them together as well as the most crucial factors being what you have told her, and how she feels about her bio dad, and this meeting.

Does she have a dad figure in her life already? Does she even understand what a BIO dad is? If you don't know her feeling you better ask. I also suggest you go slow and don't overwhelm your daughter with adult expectations from either you OR her bio dad.

I cannot imagine she hasn't had many questions about this before unless the existence of this bio dude has been kept from her for a very long time already, and if that's the case, err in the TOTAL interest of your daughter as to where and how they do meet. I guess it comes down to how well you have prepared her for this moment in her life, mom, and how well YOU are prepared for it also.

More background info may be needed besides the answers to my questions so, back to you.