Yes, it can be handwashed in tepid water and any delicate liquid wash. Squeeze out very gently as much water as you can and as you said, drip dry. I wash rayon all the time and have never had a problem.
It will shrink like mad but don't fret as it will go back to the correct size when you iron it. Iron on the wrong side when it is only very slightly damp as rayon is fragile when wet. If you have to iron any part on the right side, use a pressing cloth or it will get iron shine.
Just a note that if it has any sequins, DON'T wash it, as the sequins are likely made of geletine and will disolve.