I say yes. This is from an old thread:
Riding the canter in half seat
Riding the canter correctly and well in a full seat is difficult, and many more riders do it badly than do it well. As Allison stated above, it requires a degree of abdominal fitness, as well as correct position, relaxation and a good understanding of gait mechanics and how the horse's back moves. That's out of reach for a lot of recreational riders. I would much rather see an elementary or intermediate rider cantering in half seat, allowing the horse to move freely, than someone attempting and failing a full following seat and punishing the horse's back in the process.
There is nothing inherently insecure about riding the canter in half-seat or two point as long as the rider is in balance.
I'll add that I miss seeing maura's posts on HF...
...I often found her advice very helpful. Allison's posts #9 & #14 on that thread are also very good.
Some horses have trots that are very tough to sit. Our little BLM mustang has a trot that makes me want to pee blood, but his canter is glass smooth. Others trot nicely and have brutal canters.
What worked for me in learning to canter was to start in two point if needed, then 'half seat, and then 5/8 seat, 3/4 seat, 7/8 seat...
I think the reason is that once the horse was moving at a canter, I could spend a few strides getting the rhythm down so that I could move with him instead of struggling to find the rhythm. If I lose the rhythm during a canter, I'll go to a half seat, pause, and find the rhythm again. And if in doubt, I see nothing wrong with going to a halfseat and sparing the horse's back my jarring butt slamming down on him (or her). It certainly is not traditional western riding, but my skill level requires I do what works and spares the horse's back, and then try to get better with time. Besides, even in a western saddle, I still tend to ride a 'poor-man's' version of a forward seat.