I wouldn't do that.
A character meal is expensive. I would not want to rush through it to try and make RD.
The answer is no.
If it is 9 am park opening and your ADR gets you in close to 8, you have 30 minutes to eat, see all the character, etc. They will be letting people in the gates by 8:30 and into TSL by 8:40.
I would either do H&V, take my time and enjoy it or eat somewhere quick and do RD. I think trying to do both will not work out. You will rush through breakfast and not enjoy it and most likely get out too late to beat the crowd at RD.
However, if you are not trying to do TSL at RD, then you may be OK as the rest of the park does not open until 9, so that gives you more time.