S9+cracked front and back but not miss calibrated all ask works but af

It seems obvious you'll need to replace both the front and the back glass on the phone, which should be fairly straight-forward assuming your case isn't bent. If it is you'll probably need to replace that as well, unless it can be straightened perfectly; unfortunately there isn't a guide here on iFixit for that, so hopefully replacing the glass is all you need to do.

Ordinarily you would need to follow two different guides to replace both the screen and the back, but for your phone you have to remove the back anyway to get to the LCD, so replacing the back glass is just part of the procedure you'll have to do anyway.

You can shop around for a new screen, but you can buy it right here on iFixit if you want. I'd suggest getting the Fix Kit, as it includes both the front and the rear adhesives you'll need to do the job right.

Galaxy S9 Plus Screen: AMOLED + Digitizer Replacement Kit - iFixit

Of course, you'll need the rear cover as well, which you can also get here.

Galaxy S9+ Rear Glass Panel/Cover - iFixit Store

If you do end up needing the midframe because it's bent, that's available as well.

Galaxy S9+ Midframe Assembly - iFixit Store

For the glass, just follow the guide from beginning to end and use the new parts when you're reassembling it.

Samsung Galaxy S9 Plus Display Replacement - iFixit Repair Guide

If the worst case happens and you have to replace the midframe as well, you can use the screen replacement guide as a start, then use the rest of the guides to take out as many other parts as possible. The teardown should give you a pretty good idea of what order to do things in and anything else not covered by guides.

Samsung Galaxy S9+ Teardown - iFixit

Best of luck with your repair; let us know how it goes!