In my opinion (based on my continuous experience) hardly any touch smartphone is suitable for elderly person older than 70 (may be 75, it depends...). For elderly person it's quite difficult even to touch the display in the right place with the right strength, to swipe, to avoid unwanted touches, to use virtual keyboard (N9 has quite small LCD and thus also small virtual keyboard) etc. Much more better is any dumbphone with big and enough spaced physical buttons with big letters/numbers and good tactile feedback. Also:
- dumbphone lasts daaaaaaaaaaays before the charger is needed, i.e. no need to remember to charge every (second) day + mind also that connecting the charger may be quite difficult for elderly person particulary using the ***** micro USB (solution may be a charging/docking station) + opening the N9 micro USB door must be nightmare for elderly people
- dumbphone is usually much more shockproof (yes, elderly people unintentionally drop things on the floor) and spare LCDs and other spares are much more cheaper and are usually quickly and easy replaceable
- dumbphone software is usaually much more foolproof, no unwanted silent mode or flight mode, no weird problems and no need to ask anybody to solve it. I really like my N9 but sometimes something really weird occurs and it's necessary to find the solution.

Also, the old resistive touch LCDs may be better for elderly person, because more strength is needed (i.e. less unwanted touches) and also the nail can be used for touching the screen. Good trade-off may also be old Nokia "touch&type" devices having both resistive LCD and physical keyboard (but with small numbers and letters...).

Just mi point of view, being some kind of telco consultant/serviceman for more elderly people in my family for years :-)