from what i have read, yes and no.
yes, you can add coral and other inverts and ich needs fish to survive. but, no you shouldnt. at least not if you want to be absolutely sure your tank is ich free as it can come in with any livestock, or water, that you introduce to the tank.
if you are going to add corals in the future without quarantine you might as well add them now. if not, wait the 6-8 weeks to be sure, then whatever goes into the tank should be quarantined to be absolutely sure.
good luck