I can only reproduce this in the POC if I force IE9 into IE9 standards mode. The header that forces IE into IE7 standards mode that is present masks any misalignment. I'm not sure if this could be reproduced in the Williams app any other way? Are they only serving that header for IE8?
This is because IE9 is serving an IE7 user agent - so the DataTable configures itself expecting IE7 standards. If IE7 standards are used (which they are when not changed with the dev tools) the example works as expected.
The problem here is that the config of this app is forcing IE7 mode to the point of serving an IE7 user agent string. The issue isn't our component.
My suggestion if they want to get the page working on IE9 / 10 they need to detect those browsers server side and stop that header that causes the compatibility mode from ever being served- or just accept the IE7 compat mode. Messing with the dev tools after serving that header the table just won't work- it's been configured for a different browser.
Resolving pending discussion with client about their approach.