I'm not sure why this is only available in practice mode - I'm suspecting it is to balance out the scoring based on skill a bit more. But there is an easy way to do this - make the scoring just as in the level 9 start, but make the speed level 18. Since level 18 speed is the same as holding the down button, one way to achieve this could be to have a down button set toggle - where you can set it to be always held and thus always have level 18 speed at least
I'm not sure why this is only available in practice mode - I'm suspecting it is to balance out the scoring based on skill a bit more. But there is an easy way to do this - make the scoring just as in the level 9 start, but make the speed level 18. Since level 18 speed is the same as holding the down button, one way to achieve this could be to have a down button set toggle - where you can set it to be always held and thus always have level 18 speed at least