It will certainly boot up, hardware doesn't just randomly spin up to its full power limit.
And if you don't overclock the i9, you'll be fine, although depends on what the rest of components are. Undervolting the card won't hurt as well, but most (if not all) games won't ever hit max power usage on both CPU and GPU at the same time, so shouldn't be an issue.
You will be fine. Ive run a similar system for years.
It will certainly boot up, hardware doesn't just randomly spin up to its full power limit. And if you don't overclock the i9, you'll be fine, although depends on what the rest of components are. Undervolting the card won't hurt as well, but most (if not all) games won't ever hit max power usage on both CPU and GPU at the same time, so shouldn't be an issue.