Just got a new Telextender for my skywatcher collapsible dob and while I was looking at the moon thought I'd try some quick shots with my iphone....
The views through the eyepieces, a 20mm GSO superview, and a 15mm William Optics SWA 15mm, were amazing, and the telextender is just great...in one or maybe both (not too sure cos I took a stack of pictures, and just chose these 2....) I used an 80A filter to try to reduce the glare for the phone. The photos don't come close to doing the pure visual justice, but I'm pretty happy to be able to do this with an 8" dob and a mobile phone....
I wouldn't worry too much about using a filter, as your exposure time will be very short for the moon...less than 1/100th of a second. It won't hurt using a neutral density filter, but you don't need one.