Can you keep sepia bandensis in a reef tank with tridacnid clams?

I believe you can, but you might wanna wait for the seasoned veterans to chime in before you throw your $100 prized croceas in with a possible predator ;)

I don't see why they would bother a clam, unless it smells good.

I've heard that high light can damage cuttlefishes eyes. Is that true?. Would metal halides be too much for them.

Generally speaking, most folks keep their cephs in dimly lit conditions. It might not be as big of a deal with cuttles as it is with octos. I would wait for someone like Colin to fill you in on keeping cuttles in a reef setting.