1) Yes, TurboTax does support Foreign Income Exclusion and Foreign Tax Credit. With you moving in September you will not meet the 330 day test, so you may want to consider an extension for the 2017 return.
Note: your income from 1-1-2017 up to move to UK will not qualify for the Foreign Income Exclusion.
2) You have 10 years to file a claim for refund of U.S. tax if you find that you paid or accrued a larger foreign tax than you claimed a credit for. Source: https://www.irs.gov/publications/p514
By the time you are able to file the US Tax return (to get a Foreign Income Exclusion) you should know if there are any taxes due the UK.
