I called t-mobile (I have a 10 line business account) and asked them to match this offer...
I ended up buying the Note 8 (which has the same price as this galaxy 9 on the t-mobile site) for $30/month for 24 months = $720... but they gave me an instant $250 account credit so net = $470 (and spread out over two years).
I did have to pay the full $63.90 in taxes though.