Generally I don't think moving BT by too much helps. Just my experience, but I think having a 'normal' BT that you aim for, with the option to go a bit early if naps are rubbish, can really help LOs settle into more of a sleep rhythm, especially approaching 1yo or older.
Obviously the usual BW approach at this age is to work with A times rather than setting times. But there are mums here with experience of set naps from an early age (I only did it after 1yo) and it can be very good for angel/textbook personalities. Touchy/spirited babies may struggle more to get out of the OT that often develops when first setting nap times. Just from my experience though, what set naps AREN'T are a guarantee of the exact same nap lengths happening every day. You know when naps start because that's what you determine. But LO may sleep more one day and less the next, and that's ok. If you think that would cause you to worry though, I would stick with A times for now, perhaps aiming for a total A time in the day of 10.5h or so (typical sleep needs at 9 months being 14-15h per 24h).