I'm a bit late, but...
I think 1 min/level is fine. Although if I were creating the spell for my own use, I would probably say 4d4 (or even 2d4+4, or something), duration 1 day. I might allow for increasing the range (from 'touch' to... is it 'near'? 5 ft +1/level not sure if that's official, but it looks 'close' enough.), if you're going to make it 9th.
You would want to keep it in Strength, though. There isn't, as far as I know, a 1 spell/domain/level restriction. It would be somewhat silly, after all. Divine spellcasters can make new spells, and making one within their granted domains only makes sense (err... isn't there actually a bonus if you do this? Haven't read the spell creation rules in a while, so I could be off on that). Regardless, it's more appropriate than Bigby's for the strength domain (yes, the best clerical Strength spell you can cast was created by and named after a wizard... But isn't that always the way?)