I just did this and it works great. I only had available an M8x1.25 bolt with 70mm threaded length, 75mm overall length. Which is a tad less than I'd recommend. It was not long enough to put any washers behind the locknut, which I would have preferred.

I put two grade 8 washers underneath the hex bolt head. The idler pulley bolt hole is enlarged on this side for the original bracket and I was a little concerned about the washer deforming and loosening where it is not fully supported. One good thick washer would accomplish the same thing.

I put some Loctite red on the threads as well as using the locking nut. It's not going anywhere.

Considering how little belt wrap is around this pulley, I don't think a bracket will be necessary to withstand the shear force. I will keep an eye on it though. This simple move definitely increases the belt wrap on the kompressor. 25-30* I'd guess. The overall belt route length works out about the same. I had to fully release the tensioner to get the belt back on.