I assume these are going on standard wheels going by the tyre sizes you've mentioned.
Upping by one size is no problem and won't have a noticeable impact on speedo readings. My rears are 9.5" on the back and 265's have a slight stretch (FK452's) so to be fair the 265's on 9" rears should sit perfect.
E92 335i | 6 Speed manual | BMS 4xLED Halo Bulbs | JB4 (waiting to be installed) | BMW Performance Gloss Black Grills | BMW Performance Exhaust | Smoked side Repeaters
Aero Front Lip | M3 Lip Spoiler |19" Cades Tyrus 'Gunmetal' with polished lips | Falken FK452 Rubber
........... More to come