Hi, my 10 week old little one sleeps longer on a rocking recliner/bouncer during nap time. Is it safe to leave her in recline position with supervision? Would sleeping in recline position causing scoliosis?

Red Nose has the following information:

As there is no Australian Standard for bouncinettes, we are careful to keep up to date with reports of accidents associated with their use. To date, the most frequent accidents associated with bouncinette use are falls and entrapment hazards. Furthermore, deaths have occurred when baby has been placed to sleep in a bouncinette.

When a baby falls asleep in a propped up device the head can fall forwards, pushing the chin down towards the chest. This can lead to the airway becoming blocked and reducing airflow.

Tilt your own head forward and place your chin on your chest. Try to breathe through your nose. Can you breathe freely? No. Babies breathe better when they are lying on their back on a firm, well fitting, flat (not tilted or elevated) mattress.
https://rednose.org.au/article/bouncinette

The “chin on chest” position can pose a risk to baby, as their airways are very soft & small & can become “bent” (like a straw) if in this position for an extended period. 

This information also applies to some slings/baby carriers/hammocks
https://rednose.org.au/article/search/eyJyZXN1bHRfcGFnZSI6ImFydGljbGVcL3NlYXJjaCIsImtleXdvcmRzIjoiY2hpbiBvbiBjaGVzdCBwb3NpdGlvbiJ9