The kiddie tax law was modified by congress at the end of last year (part of the SECURE Act), so this didn’t give the IRS, or the commercial tax preparation companies, much time to update all the forms and software. That’s why things have been so delayed.
The major modification for the kiddie tax is that for tax year 2020 it will go back to using the parents’ highest marginal rate to figure the tax, as opposed to using the estates and trusts rates and brackets. For tax year 2019, the returns that people are working on now, the taxpayer has the option to use either method to calculate the tax, and there is also the option to go back and amend tax year 2018 returns to use the parents’ rate instead of the estates and trusts rates.