As Dr Wu has pointed out, it is generally safe to commence acne scar treatments whilst on Isotretinoin.
Personally, 2 main factors will determine the treatment plan:
1) Condition of your skin
If your skin is irritated, flaky and sensitive from the Isotretinoin, then it might be best to delay intense ablative treatments till later so as to minimise the side effects associated with such treatments.
2) Severity of your acne
If you are still having constant outbreaks/ cystic acne, then it would be best to treat your acne first as acne itself can cause further scarring and would be counter-intuitive if you were to start acne scar treatments now.
Treatment of acne and scars do take time so be patient and discuss your options with your doctor.
Hope this helps.
All the best!