Hello ,
If this you want to do for one day/time activity, then you can do it manually.. with scehduling and remove schedule with updation of little frequency run(say 2 hrs) . may be u already know this 
But if this is permanent then i think we dont have any such options.
But you can handle this by adding one abap program step inside process chian.. & while run of PC just check in abap step what is time(say 09.00) then dont run PC else run will be as usual.
Regards,
Hitesh