Can I apply for another tourist visa in December after staying in Thailand for 8 months on various tourist visas?

Hello, I am new and I am sure my questions were discussed several times here in this group but if you could answer me I would appreciate.

1- I arrived in Thailand on April and got 1 month visa in airport. Then I did extention in Phuket for May. (2 months)

2- I applied for tourist visa in Malaysia/Penang and got June July visa + August 30 days extention. (3 months) (BORDER)

3- I got tourist visa for September and October from Malaysia/Penang again and I did 30 days extention for November. (3 months) (BANGKOK AIRPORT)

8 months in total... Is it OK for me to apply for another tourist visa -in another country, not Malaysia- (by airplane) on December?

Is it true that you are able to stay on tourist visa in Thailand, 9 months in one year? And you have to spend 3 months outside of the country?

“When you have student visa you only go to immigration office every 3 months.” Is this correct?