Are you adding more sand? Sand bed depth from a 55 to a 90 will be smaller. As long as your Sand bed is pretty healthy it should be ok to re-use it all. I would add the fish right away as well. If you have corals, you might wait a bit till the dust cloud settles. They can be irritated by the sand.
It will be very hard to aquascape when you can't see in the water
I have done this twice with no casualties but my sand smelled good when I removed it. On the last move I tried to put the top layer of sand in a separate container than the bottom layer. I had a small spike but nothing major. I left my delicate corals in a rubbermaid over night with a heater and a PH
till the water was a little better.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,