Vagrant: multiple playbooks for ansible provisioner

no it will not be valid

If you want to run 2 playbook, you would need to run the ansible provisioner twice, this can be done like

 config.vm.define "repo", primary: true do |d|
    d.vm.hostname = "some.hostname"
    # Create a private network, which allows host-only access to the machine
    # using a specific IP.
    d.vm.network :private_network, ip: "10.10.2.90"

    # First playbook
    d.vm.provision  "playbook1", type:'ansible' do |ansible|
      ansible.config_file = 'ansible/ansible.cfg'
      ansible.playbook = 'ansible/playbook1.yml'
      ansible.sudo = true
      ansible.inventory_path = 'ansible/inventory/site'
      ansible.host_key_checking = false
    end

    # Second playbook
    d.vm.provision  "playbook2", type:'ansible' do |ansible|
      ansible.config_file = 'ansible/ansible.cfg'
      ansible.playbook = 'ansible/playbook2.yml'
      ansible.sudo = true
      ansible.inventory_path = 'ansible/inventory/site'
      ansible.host_key_checking = false
    end
  end