As for reliability internal lens could be more reliable because extruding lens structure is more complex. (most reliable would be manually operated zoom)
I think internal zoom is more rough handling resistant because of less complex structure and it doesn't extrude.
On the other hand lens of internal zooms is in such place that it might get fingerprints easily while handling camera, also you have to remember to keep fingers out of way when taking photos.
Not really, limited space causes quite a lot limitations to lens design.
Which one is better just depends on use/requirements. For example internal zoom mechanism is quite mandatory for those cameras which are water proof.
In normal use extruding lens designs works well (huge amount of cameras use this design) but if camera would be in pocket always for example in rougher work hits to lens cover wouldn't do good for lens extending system... but I think there's also cameras whose lens completely retracts inside body and then separate cover in front side of body is slided over lens which is propably equally durable against bumps.
Also between those two cameras t9 is definitely going to have extremely bad red eye problem when using flash because it's just too close to lens... and lens seems to perfectly placed for "photographing fingerprints" when you prepare to shoot.
