I'm not familiar with Odoo 9, but you should be able to create multiple sequence numbers and apply them using an Automated Action.

Here's an example that's similar to your requirement (in Odoo 12).

Start by enabling developer mode and navigate to Settings / Technical / Sequences

Create a new sequence (or copy an existing one):

Navigate to Settings / Technical / (Automation) / Automated Actions and create a new Automated Action:

Python Code:

for record in records:
  if record.x_studio_order_type == "Consumer":
    ref = env['ir.sequence'].next_by_code('consumer.sale.order')
    record['name'] = ref

We need to use the same Sequence Code [consumer.sale.order] as the one we used on the Sequence we created above.

You would need three Sequences and to include all of them in the Python Code:

for record in records:
    if record.x_order_type == "Domestic":
        ref = env['ir.sequence'].next_by_code('domestic.sale.order')
        record['name'] = ref
    if record.x_order_type == "Export":
        ref = env['ir.sequence'].next_by_code('export.sale.order')
        record['name'] = ref
    if record.x_order_type == "Disposal":
        ref= env['ir.sequence'].next_by_code('disposal.sale.order') 
        record['name'] = ref

https://odootricks.tips/set-sequence-numbers-for-sales-orders/