I’ve had the same problem with mine.
I ended up putting mine in its own loop from an A-B box that has a ground lift separating it from the rest of my signal chain.
I would rather have it inline with the rest of my pedals but this will work for now.

How are you powering your B9? I’ve found that the B9 doesn’t like to share voltage on a daisy-chained power-supply such as a Visual Sound 1 Spot; a very annoying, very noticeable constant high, droning, whining noise can result. Simply power it with a current-capable separate 9vdc center-negative power-supply or an isolated 9v supply such as those of the Voodoo Lab Pedal Power line of power supplies. I’d bet that the C9 is the same in this.

My Strymon pedals also need either their own individual power-supplies, or that of a good PS like a Voodoo Lab Pedal Power unit; they exhibit some odd electronic ‘hash’ in the background if powered on a daisy-chain.

I use a few of these short extension-chords, that light up with internal LED’s, to save space on my outlet-box; they’re great for wall-wart power-supplies…