What do you mean 9s tiagra/105? A 105 chain and cassette on a tiagra RD? I did similar upgrades from 8 to 9 on both my mtb and my roadie a couple of months ago with the same exact problems on both. For my mountain bike I ended up taking out the cassette and tightening the screw/pin that holds the first 6 or so cogs together and then running through all the adj screws again and for my roadie I ended pushing the RD into the correct position for riding on the small cog before tightening the nut that holds the cable (needed two sets of hands for this). The number of chain links might be a factor, but I'm not sure (its a ? I just posted). Other than that I don't know what to say except for I know how frustrating it to not have it work after going through all the adjustments.

Oh, did you set all you tension adjustment thingeys (I have 3: in line barrel, downtube, and the screw on the RD) to the lowest level when tightening the cable to the RD? I find it helps a lil in later adjustments