Hollands can often have very light rufus but he looks too light to be an Opal, even for a holland. He could be a Broken Blue Seal Agouti. But I don't see any body shading so I'd just call it Broken Squirrel, which is both more common and a recognized color unless you were 100% positive that he came from shaded lines (sable, or smoke pearl. I wouldn't trust sable point to be shaded lines, in hollands sable points are quite often sallanders. And tort is not shaded)
He's cute. Good luck with him