9-speed to 10 or 11-speed conversion
Yes, it is possible. Just be prepared to replace every single drivetrain component. If you go 11-speed you will also need a new rear wheel because 11-speed cassette needs a wider freehub body and possibly new brakes because cable pull changed slightly with 11-speed.

The standard advice here is to not do it because the cost will be close to new bike, but Look frames are quite high end and new bike with similar quality frame would be far more expensive than any random Ultegra bike.