The easiest way to avoid this is to quote specific postage to the US, then a flat rate to the other locations you post to separately (making sure you exclude the US).

When you do the postage options, quote one price to the US that includes the $9 surcharge on any items that are over the threshold. That way, only US buyers will see (and pay) that amount of P&H.

You can't update listings via Turbo Lister with that option, but you should be able to do it in bulk with Selling Manager (or in batches if you have a few different P&H charges).