I'm planning out a box for my 8" Orphan driver. Using 3/4" mdf, outer dimensions are 12x12x15, driver displacement is approximately .15 ft³, and I am thinking of using a 2x9 inch flared aeroport to bring the box specs to 0.69 ft³ @ ~34 hz.

Is this an adequate port? Or am i missing something?

I'm pretty new to round ports, as I have built only slot ports. Any help is appreciated.

IMO a 2" diameter port is not enough. 3" at minimum.

For working out the port length use this calculator:

http://psp-inc.com/tools.html

Alright thanks. I need a 22" length to get the tuning i want with the 3", but precision port doesn't offer their kit to be that long, and they don't have any elbows or anything like that. I need to bend the port to get that length obviously, so where is the best place to get the stuff that i need?

Check this link: http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=143&CFID=2883261&CFTOKEN=17112502

You should be able to find what you need.