Hi Sid and welcome, buddy.
Re: C6th on 8strings: On my non-pedal guitars I came to the conclusion some time ago that the bottom string of an 8 (Bb/C/C# or whatever

) adds very little to your scope compared to having the tonic down there - a low C. So I messed around until coming up with (lo to hi) CEGACEGD - the top D is the one pitched between strings 3 and 4. It is a very common first string on 10 string pedal steel, although it usually
replaces the high G. But, as I like that top G and we don't have the advantage of the extra bottom strings of a 10, I did away with that bottom 'whatever' and shifted the main tuning to slots 8 thru 2

. That added D provides a lot of fancy runs that would otherwise need much bar movement and I haven't missed any chordal properties of the low range. I would think the fact that you have pedals won't make much difference to the general principle.
As to your E9th; a lot of pedal guitar licks come from those (so called) chromatic strings. But if you put
them on, you will have to lose something else lower down and not have some other, and maybe equally, important voicings

. So the simplest way is to string up without the top two "chromatics" and get used to the rest of the tuning until you (inevitably) have to get a 10st!