I know that bct is strict in that it is work for 9 weeks straight, but I don't know a lot about ait or osut. What I want to know is if osut is as direct as bct or is still split half bct half ait, if ait is any different?

OSUT is only for specific MOS's, while BCT is a phase all entry level enlistees go thorough regardless of MOS.

BCT is Basic Combat Training.
OSUT is One Station Unit Training.
OSUT you stay at the same unit through BCT and AIT.
Some MOSs however, you may attend BCT at one post & AIT elsewhere.
ie:A Cook could got to BCT at Ft Jackson, then will attend AIT at Ft Lee.

I know that stuff, what I don't know if it stays the same, the working 6 days a week, 17 hour days. During ait or the second half of osut, is there any change in day to day schedule?

BCT is hell.
AIT is mostly classroom.
OSUT is BCT and AIT combined for one long period of hell for certain MOS where just a little bit of hell is, well, just not enough.

Infantry OSUT is like being in BCT the whole time except for the last 2 days.

It all depends on the MOS- 11 series- mega woods time, same for most combat arms. Tech MOS- mainly class room. What you didn't think that the Military was 9 to 5 did you?